I basically just try to trap her on the ground or low to the ground by throwing a turnip just over and behind her head if she's facing me to cut off her DJ away zones and therefore force her to stay, move forward, or drop to the ground (and then you just plough through her attacks with fair if she swings at you and otherwise just space fair and go in and then do gay Peach things [more information on this in paragraphs below[). If she's got her back turned to me, I adjust the aim slightly to arc and hit the far end of her body (I guess it would technically be the front of her head?). This is basically to cut off the escape zones the same way the turnip does when you lob it behind her when she's facing you, except her DJ bair has less momentum than her DJ into fair and the threat of turning her around often makes her move forward and attack into you, which can create opportunities to counterattack if you can hit the ground and shield in time (approaching bair is very punishable). And if the turnip actually just hits her, if all goes as planned and it hits her forward then it combos into a free aerial. Otherwise it pushes her back and forces her to face you (which means she has to spend time to adjust her stance when she finds a second to compose herself) and that's all time you can spend figuring out how to proactively hit her, gain control of the stage, and so forth. Also if she's facing you then your fair beats her everything in air to air unless she stuffs it which is sweet.
After she gets tired of being forced to look at you and then faired, she'll have to do something bizarre like catch turnips / attack better, or land. I've never really seen a Puff do the either of the first two effectively so let's focus on the third. Once she's discouraged from attacking in that position, she's gonna land and try to find a way back to the positions in the air where you can't really do anything to her unless she starts to run low on jumps or she does something stupid (and during this, she'll be trying to align herself to hit you or setup pressure or other lame Puff nonsense). So basically when she's grounded, you're at advantage and the goal here is to use Peach's better air-to-ground game and superior actual ground game to do damage efficiently and keep Puff from reversing the situation and gaining mid-stage (or chasing you down with momentum). Fortunately, Puff's only real ground attacks are her grab, u-tilt, f-smash, and dash attack (other notable things to watch for are her crouch and shield). None of those are really that effective vs what Peach will be using so long as you understand why Puff's ground game is really more polarizing than actually effective vs most characters.
So, we're gonna start with rest because it has to be addrest or none of anything above or below matters because you cannot keep pace with repeatedly dying at 9%. You are not Falco. When I played Abu in our seriouslies at TBH2, aside from the first match where he rested KOed me like 3 times I didn't really get rested much and I won three of the other four matches pretty handily. Currently, the only rest setups that Puffs typically go for on Peach are u-tilt at low percent, various forms of uair at specific percent ranges, and on occasion something bizarre like pound or another aerial into rest (mercifully they haven't learned about the nonsense that is ledgehop rest vs umbrella and its option tree but don't tell them that). So basically the major rest setup that seems to cost Peaches matches and create this terrible fear of using Peach's shield (which is an amazing tool in this matchup against everything but basically spaced bair) is the u-tilt because of its tendency to shield-poke. People don't typically expect to be shield poked, resulting in bad DI (or no DI) and then they get pinged and Peach Puff is impossible 7-3 matchup and nothing will ever change that. Uair and the bizarre setups with pound and the side-hitting aerials (and dair I suppose) are generally easier to see coming because of the positioning she needs to hit those and then combo off them into rest; for this reason, they're often easier to crouch-tech, DI out of, and so forth so I'm not gonna focus on them because they don't seem as costly as u-tilt.
So, the thing about u-tilt is that avoiding the shield poke is in fact super easy but not many people know a whole lot about hitboxes or why shield pokes even happen. Anyway, since most of you just want the answer just angle your shield a bit down and if it's small, decompress whichever shoulder trigger you use by a bit and then angle it down to avoid losing to u-tilt rest at low percent. Okay, now for the explanation of why this is necessary. Basically, Puff's u-tilt's opening hitbox is a dot around her feet. Because the hitbox is so small, it avoids the shield area near most characters' feet (in order to shield poke, your hitbox must hit part of the other characters' body without touching the shield). As a side note, I actually think this is a balancing feature to characters with relatively smaller hitboxes like Samus but it just didn't work out as effectively as the designers intended but that's neither here nor there. Anyway, in Puff's case after the red dot appears, the lack of shield touching it ensures the opponent got hit and then pops them up into certain doom. However, this is exploitable because angling the shield down covers basically everywhere the u-tilt could hit once she's inside the space where characters generally have their feet exposed. In addition, the move itself is laggy and very easy to ground float aerial OOS on in retaliation when it hits the shield (ground float uair OOS is especially fun on it). Moreover, ground float FC aerials actually has a very solid option tree for follow ups if you actually procure one in a low percent range because nair combos into itself or other aerials and then on a lot of levels you can then zone her further by plucking a veggie and manipulating where she can go with it, or baiting her into attacking out of position and countering it appropriately.
I'm gonna make this its own paragraph 'cuz there's an art to pressuring Puff and maintaining superior positioning. The only real rule of baiting her panic attacks is to remember you're slow and it's easy to overextend. She basically wants you to overextend and then hit you so she can regain composure. However, her attacks only win vs yours in specific positions and she's not miles faster than you (and your attacks are scary on the basis that they all do like 14%, have medium kill power fairly uniformly, and have bonkers startup and priority) so it's easy to keep superior position by simply threatening her and then not committing. Also, remember that her counterattacks that move her into you (DJ into you > fair, etc) can often be eaten at lower percents and then naired on if their spacing isn't very perfect. Don't underestimate the power of simply trading hit for hit as a means to kill her or maintain posture if you're winning or relatively close in a race. Hell, even if you're losing by a chunk it might be worth it just because as she runs out of jumps she starts to be pressed to go low or hit a platform to refresh, which can both be exploited pretty hard by a savvy Peach.
Okay so now I'm gonna address her ground game. She likes to punish landing lag with f-smash and grab because she thinks she's clever. She also likes to f-smash in the direction of descending aerials to take that into consideration. Some kind of FF land that doesn't lag you up (float or empty land basically) into shield can often **** her up for this. She might switch to grab, but that's easy to out-space and therefore tempt f-smashes and dash attacks as her go-to on the ground - the latter of which you can u-smash sweetspot OOS on which is (c) Riddlebox. In general, her ground game is pretty limited so there's not much to know in terms of how you beat it since basically all of it is shield punishable or her grab, which polarizes your behaviour and hers based on whether you can be grabbed immediately or not. Defensively, she'll crouch and block to make dash attack too risky to really be considered so you can cross that off pretty quickly. If she blocks in general within a certain range you can just go in with an FC aerial and then go berserk on her shield. In general, people need to be better at shield pressure and understanding the timing windows you're trying to hit vs Puff because her OOS options suck but then the fear of... I don't even know what... causes them to back off when she super duper vulnerable. Let's break this down: Puff's OOS options include a really slow jump, really slow WD, shield grab, a frame 8 JC u-smash that hits behind her (not useful since Peach should pressure the front of Puff's shield whenever possible and its hitbox isn't really big either), and an above average roll forward. Roll back is difficult to directly punish if she gets it off (though you can often hit through it if your pressure is good) but if you see it quickly, you can often turnip after your aerial or such and then toss it into her space - if she shields after the roll or crouches or jumps, it'll often hit the last two or bounce around awkwardly on the first, which enables you to set up your control of the middle. Peach likes controlling the center stage box, even vs balloons. Roll forward is invulnerable frame 2 but honestly rolling into or by Peach is generally weak and everyone should know this by now.
Okay so her other major ground defense is her crouch. She likes to make you aim your aerials low to hit her crouch and then spontaneously f-smash because you've delayed your window. However, this is easily beaten by landing and blocking and all that crap mentioned above. Another really good counter is just throwing ground turnips at her (just make sure the turnip will hit). It's annoying, easy damage, and it makes her have to do something. If you get caught pulling a turnip as she moves in with a really aggressive ground movement, just remember you can throw the turnip down during jumps and that you also still have your float aerials and can feasibly out-time her with them even after plucking a veggie if she's WDing in.
Another good thing vs her crouch is to simply threaten to down smash her, since very few players know how to crouch-tech it into a rest setup on reaction and even if they do you can probably DI for the u-tilt when you see the tech. The chance of you hitting 30%+ on hit with a d-smash is far more likely than you being pinged. The beauty of this threat is that most of the time you won't have to worry about them knowing to crouch tech the d-smash either because the threat of it causes them to do everything to avoid it. This means you rarely hit a d-smash but you often create an opening for other things (so the d-smash is more of the bluff or elephant in the room). To do this, if you're just outside her f-smash range, all you do is you just kind of walk towards her when she's crouching and then shield if you see her twitch or suspect the opponent of getting antsy. The shield is basically because her only real attacks that control any space on the ground are her dash attack and f-smash (and arguably her d-tilt I guess) because they're her only ones with any real range. But they're also highly punishable on shield, so odds are if you walk towards her with a super scary d-smash threatening to pop a cap in her bum for crouching then she's gonna swing or dip (probably WD back or jump back). Since you can float OOS (or float fast fall turnip), her moving back isn't really a big deal and the former is beaten by shielding. It helps to know the max-range of the d-smash's first hit though or else you'll probably wind up walking close enough for her to grab you if you block and then that ruins this. Her slow jump works against her here because it makes it so that she has to act early if she wants to use the air as an escape, so this makes it easy to tell when it's okay to d-smash or not.
That's enough for now. I've posted this before actually so I think that's enough period LOL.