Ok so I read through all of these. Now I'll put my say in this.
You wanna remain mostly on the ground and have a turnip in hand while being close to him. Do not go in the air vs him unless you see a pattern of him trying to come at you with fairs. From here you can short up fair him or do RAR bairs as an approach. If you are close to him and you have him shielding, you can do SHORT hop dairs on his shield.
While staying close to him, you can QFR to staying moving and space pivot tilts. It's a good anti air and can snuff out alot of his approaches. DO NOT try to punish his side B with upsmash unless he does it high. If he does it level with you, you are likely to get hit. The best options to beat that move is a spaced fair, early timed bair or a Fsmash (Best option). If he does does leveled with you , you can also full hop dair to avoid the hit and then hit him from above. Single jabs as mix ups are good her (even if its not her brawl jab) Since people usually expect her second jab. And don't use any slow moves or moves can leave you over for a while. Such as Floating bairs/fairs. Attacks to use uplcose on him is as follow:
- Short hop dair. You can go into float if you do this quick enough and then space a nair and be safe from counter attacks vs diddy. Or frame trap with another dair while floating.
-Dtilt If you hit him with a space dtilt on shield, he can NOT Punish you at all.
Nair- Fast falling nair is safe as well as a spaced grounded nair.
Now if you stay out of his attack range, you can still damage him with turnips. If you do a floating dair and timing your landing on shield, you can run back to stop assults out of shield and punish with a reverse turnip toss. Then z grab it and floating in for pressure and do it again, or mix it up. As I said before, you don't have to challenge anything this fool does. So why risk it when you can deal damage from a distance. rack it up with turnips. Turnips also slow him down and he has to do alot of guessing where you will throw it, not toss it or attack with an air attack while holding it.
Your shield is also your best friend to punish air happy diddys. You can run in with shield and punish him out of it for dishing out fair.
So after learning how to deal with this jank character and fighting Jtails in tourny (I nerly beat his diddy) This match up is not bad as people make it to be. Peach can take him. Seriously, just don't give this fool what he wants and he is having a hard time. If he is aggressive, just keep moving and don't challenge a damm thing he does. He will leave himself open. or forced to defend. Giving you a chance to dish out the damage. Jtails says he does not like fighting Peach as diddy at all. And he rather go ness. He feels Peach can do alot of crap to diddy. People just dont know how to deal with his nonsense and he gets away with murder.
The main issue here is people don't know how to avoid grabs well, which diddy just gets free daage from. Thats his game. most diddys just wanna grab and what they will go for alot. This is how you avoid it.
- Stay moving
- Stay grounded. Being in the air can give diddy a chance to punishing your landing or forcing you to block.
- Play it cool when he has a banana. He is waiting to use that for a grab. Don't give him a chance to hit you with it.
- Space your moves
When diddy has a banana, he is not much of a threat due to him not being able to use his normals. From afar diddy will just his peanut gun to try and force and approach. and when he sees one, he will wait for an attack to counter with the banana or wait to block/evade a move, then go for the grab. If he is shieldng, leave him, he can't shield forever. You don't have to challenge that shield and give him a chance to grab you. He will have to move when the shield shrinks on its own.
If he is dishing out move, don't challenge it. That's another thing I feel people give to diddy. If he is swinging, let him swing. If he does and you are near him, this is your time to counter attack on his landing or force him to defend.