watching match 1...
@ 0:14, 0:21 You did a nice job by hitting peach with your Nair, however never land near Peach or you're going to get Dsmashed (which actually happens in the video). The purpose is keeping Peach away, not running towards her.
@ 0:18 I'm pretty sure you had time to reverse SHL + other stuff. Shielding followed by a shield grab or even better a shield shine is sometimes good but definitely not abusable. Peach usually connects double Tap As (if possibly) and a Dsmash to her aerial approachs, which results deadly if used along with float cancel. Also, if Peach spaces properly her aerials Falco will have no other choices but rolling away from his shield, because shield shine and shield grabs will have not enough range while Usmash out of shield won't be fast enough.
@ 0:58, 2:32 you missed a spike opportunity, spike would have definitely killed peach there, while ABA/ANAs usually don't, expecially on large stages. ANA and ABA send Peach off stage but she's quite hard to edgeguard, if possibly always use spikes on her.
@ 1:08, 1:16 watch out for those full jumps approachs. Peach can easily DD + grab/dash attack them or Short hop + ANA them if you don't use them fast enough. On FD jumping is usually pretty bad. If you happen to jump try to use wavelands/double jumps in order to get away.
@ 1:26, 2:08, 2:24 your opponent missed DI on your Uthrow. When you happen to notice this, use SHL + grab followed by Uthrow + Dair near an edge in order to get an early kill (should work at about 50-60%).
@ 2:00, quit using tap As and Fsmashes on Peach. Both can be easily countered with shield/ CC+ Dsmash or nearly any other defensive move from Peach. If you really want to close combat Peach use either grabs (only when Peach doesn't expect them, though.. they're quite easy to punish if they miss) or aerials followed by shines. Shines are very important because once Peach gets tossed in the air landing may be problematic for her. Speaking of the aerials ANA + shine is faster, more ranged and harder to punish but ADA + shine is the only thing capable of stopping Peach from CC + Dsmashing everything you throw at her (and not even always..).
@ 2:04 try to find other ways to recover.. running in a Dsmash without teching isn't really the best. Up Bs towards the edge and short illusions sometimes work. In general, aim for the edge like you did at 3:00 or Peach will just follow you and Dsmash you to death, like she did from 2:39 to 2:42.
@ 2:46 what you did was nice: punishing Peach's mistakes is the way to beat her and it's particullary effective if Peach is landing and forgets to space away her aerials. Dair out of shield, Nair/Bair out of shield or shine out of shield are the best punishments. Sometimes Usmash works too but it's a bit more risky.
on match 2 you just lost your concentration which is awful. Without concentration you did a lot of mistakes you surely know how to fix, like approaching Peach on the rock pokemon stadium or getting wrecked by Dsmash so hard. Also I noticed you timed bad your approachs and didn't use lasers enough. If you want to beat Peach you mustn't approach her unless you have no other choice and spam lasers as much as possible.