Unfortunately, that peach was complete garbage so it'll be kind of hard to give you solid advice, but I'll tell you some things you should be watching out for against competent peaches. My main training partner is a peach/sheik, so I have some good experience in this matchup.
Don't be so eager to attack a peach sitting on a platform when you're below her. Dsmash will beat anything you throw at her. You can use this to your advantage, however. Try to bait out the downsmash and then hit with a uair, fair or usmash immediately after. If you're too slow, you will get hit by another dsmash.
Turnips...try to catch them more. It's hard to predict when she's going to throw them, so just jumping at her and pressing z, or even doing it on the ground is risky because if you miss, you whiff a move, and that's never good for ganon. I like to shield turnips, and then jump to catch them as they bounce off my shield, if the peach is far away enough. If you do this, try to estimate how much time it would take for the peach to get to you. Because a good peach will try to charge you before you can throw it. If she can't get to you in time, throw it and then followup with a fair. So many peaches will put their shields down after the turnip. And if it looks like they won't, you can grab.
On peach, you should be uairing d throws at low percentages. Maybe throw in a usmash at medium percentages if she ****s up the di (don't count on it) and a little higher it's best to do bairs off of dthrows if she dis behind you or stays above you. You chose uair off of dthrows a few times when you could've killed her with a bair, or at least put her way off stage.
Edgeguarding peach...reverse uair is your best friend, start using it more. Wall of pain reverse uairs strategically and peach actually has a hard time getting back. The key is never to commit too much, or else she'll fast fall into the ledge. Also do not go for dairs when the peach is floating below you waiting to umbrella. I discovered this the hard way. What can happen is the she'll up-b, it'll beat anything you do, she'll fast fall right to the edge of the stage and dsmash. You'll eat a bunch of percent, maybe even be thrown off stage and be very unhappy. So whenever peach up-bs, never challenge it from above. Get the **** out of there before you eat 30%. You can, however try to fair her as soon as she's landed.
One last thing, in the neutral, dsmash-happy peaches will get ****ed if you challenge it with dair. Peaches are used to just auto-piloting dsmash to beat out approaches. Not against ganon
