im super unqualified for this lol. my advice on videos is rough around the edges
but ill give some thoughts anyways. anything for community smashers
general advice
i think you should pay attention more to the opponent and react accordingly, sometimes you seem to just be going through the motions of what you "learned to do" as opposed to responding to actions that sheik make. one example is early in game 1 where at 1:49 sheik fullhops towards you and youre doing a shl, you have more than enough time to react to the fullhop with a shield or something of the sort, but instead you get caught during your wavedash lag. if sheik is descending on you you dont want to be putting yourself in lag. theres more situations like this but i want you to go back and watch the match to identify points where youre just "doing things" or "going through the motions" as opposed to reacting. tldr - be more mindful of your opponents actions, and make sure everything you do has a reason behind it
also i think most of the damage you receive is from when you overextend a punish. as a falco you want to know when your guaranteed combos end and focus on reacting/reading sheiks defensive options after your combo has been dealt (presumably with her in a worse position, meaning that she has more incentive to flail a little to restore her stage control) go back and watch when you get hit, its usually because you tried to force a combo to continue when realistically you dont have another guaranteed hit anymore
finally this is just a neutral game preference but when youre lasering sheik you need to pay more attention to how the sheik is reacting to your lasers, as well as how she reacts to your advancing laser or retreating laser. sometimes i feel like you just decide "okay im lasering and now im gonna start advancing" with no real reason to do so
specific things to point out
game 1
i hope you told the sheik after the set that he can autotransform by holding A before match starts <_<
1:47 example of an overextension - you get hit by dsmash at 0% and try to punish it with dair, but you're just a hair slow and the sheik shields it.
interestingly you space the dair right outside shieldgrab range and successfully bait a shieldgrab, but since you were too concerned about the fact that your dair got shielded you did a panic "get-off-me" move (jab > dtilt) instead of realizing the perfect spacing you set up.
the reason i call this an overextension is because realistically you were going for the dair punish...to me that was your dair's intent (as opposed to baiting a shieldgrab since you didnt exactly punish it effectively) in this case you were just a hair from overextending since if you were any closer the shieldgrab wouldve punished you
this is what i mean by overextension. try to find other points of the video where overextending actually cost you
something else i want to point out about 1:47 is that you shouldve noted sheik's backroll after whiffed grab. this is something the sheik will repeatedly do over the set as she whiffs grabs
1:50 the example i brought up earlier about watching the opponent more carefully
1:52 wakeup turnaround utilt is a pretty slow getup option and can be punished by a faster sheik (i think), but it does work out in this case. remember low% sheik can also crouch cancel your utilt, and a lot of sheiks like waiting with crouch outside your effective range
1:53 im not sure if the charge fsmash was worth it. i know you tried to read sheik not doing anything as she came down (which did happen) and you simply mistimed your fsmash, but realize that charging fsmash in this position gives the opponent time to react to your charge and drift away.
2:10 recognize that you have the ability to cover multiple tech options in this position. personally i would cover tech in place/missed tech with dair (as you did here) and then react to tech towards ledge with grab. you also have the option of covering both techs with dsmash, but you'd have to react to the tech really well to time it properly. if sheik techs towards center then it resets
2:14 aim for where the opponent will be, not where they already are. notice how you aimed for sheik's double jump after she already reached the apex of that jump? theres no way that would hit since she already started falling by the time you started moving
2:19 if you let go of your control stick instead of drifting towards the stage the usmash wouldnt have hit you and you wouldve hogged the ledge
2:28 late dair into shinegrab would prevent the shieldgrab attempt here
2:31 the way you spaced the dair, theres no reason for you to jab afterwards since you already crossed up. be mindful of your spacing. btw one thing i like to do after crossing up with an aerial is catching oos movements with utilt
2:32 i would suggest utilt or sh uair for anti airs. i assume the fh uair was supposed to be usmash or something
2:38 you ended up on the top platform with those lasers when you should have ended your lasers with you by the ledge (or at least on the same platform) for easy ledgehog. this cost you your edgeguard setup - remember that the edgehog setup is more important than taggin sheik with a few lasers during her recovery
2:53 keep your movement simple inbetween stocks!
2:58 this was a bit of an overextention in that while you did have time to followup the shine with a janky doublejump fair or something, you definitely didnt have enough time after an empty shorthop and shouldve just waited
3:04 youre going to have to start recognizing when the shine will combo after your dair based on spacing. in the beginning a lot of your shine dair will whiff the shine since dair puts their hurtbox right out of the way of your shine (because of their in-hitstun animation) which is pretty annoying. in this case utilt wouldve worked out
3:08 even though the ftilt whiffed you should notice that the sheik is starting to read your lhdl's
3:11 that fsmash somewhat cost you the stock here. recognize the combo was over and just react to sheiks return attempt
3:16 if you want to cover side plats above you without risking getting hit i recommend sh uair. dont do this vs peach dsmash though
3:29 ??? what are you doing the sheik is invincible ???
3:40 overextended grab, you didnt have enough leeway to cover multiple techs in this case. after the jab attempt the positions were reset
3:42 sheik whiffs her grab and does a backroll again
3:44 why would the sheik be there after your laser?
3:52 slightly overextended dash attack here
i want to point out that a lot of the scenarios here the sheik can actually hit you with nair oos but doesnt because i dont know he knows how good it is. vs a stronger sheik you definitely want to be more mindful of that option
3:54 you should observe how sheik comes down from platforms, almost always it involves some falling aerial
3:58 sheik finally punishes your lhdl successfully. i wont say you spammed it too much though since for the most part sheik had a ridiculously hard time hitting you out of it, but i definitely would have stayed on the safe side and tried to wait out some attack first.
on a related note, i want you to learn invuln ledgedashing with falco. its very useful
4:47 i see a trend here...you want to be careful of sheiks options when shes coming down from platforms in general. its a strong position for you since if you react then its usually easy punishment for you. fair is a strong option and can knock you offstage or start some nasty sheik shield pressure
4:49 at this point sheik is already very confident in the fact that youll lhdl. after the first punishment you should have already recognized this
4:55 this is the most falco-ish sequence ive seen in my life...victory by advancing fsmashes
game 1 wrapup: i think you did ok. almost all of the times sheik hit you was either because you overextended or you bought into her false openings. you also got tagged by her a lot whenever she fell from platforms with an aerial, and those situations i want you to play more reactively and patient since she hits you when youre just throwing stuff out on the ground. the takehome message is to recognize when you should switch to patient/reactive play, and for the most part its either 1. when your guaranteed punishments end, and 2. when the sheik makes commitments or puts herself in a poor position (ie on platforms) which thus makes her more prone to flailing to regain stage control
game 2
im going to be a little less specific for this game
learn your firebird angles so that you can ride the wall to the ledge. and also dont feel pressured to have to start firebird so high, it makes it easier for sheik to cover
game 2 wrapup: similar advice to game 1 except i do feel like youre much less comfortable with this stage. sheik successfully pressuered you onto the platforms a lot which ended up getting you tagged a bunch by her big disjoint attacks...however i personally dont think its too bad of a bad stage for this matchup, you just cant use your laser as much. the key here is keeping sheik pressured while playing mostly defense, as well as moving away from her attacks preemptively for counterattacks. i say this because fod plats limit everybody's approach options, which makes reading approaches to counterattack much more effective due to reduced approach options overall. i personally like using low plats a lot to limit their movement, for instance if we're on opposite sides of a plat i know that the sheiks only approach option is dash attack (she can also tag me with needles but w/e)since she cant really fall down on me with an aerial or anything
im not gonna go over the mario matches either <_< should just stay falco mannnnnnnnnnnnnnnnnnnnnnnn
with all that said, your falco is not bad imo. im impressed :) hope this helps at all LOL