It honestly looks like you don't understand anything about fighting Jigglypuff and how to pressure with Sheik. So I'll explain my thoughts on that, and then give you some specific style advice.
Some notes: I used to think this MU was just a typical grind with Sheik vs. floaty only throw sucks. However, lately, after a brief conversation with Dr. Peepee about some of the general weaknesses he feels Puff has, and some evaluation of positioning and other factors that go into this MU, I think the camp game is self-defeating. For a variety of reasons.
Instead, establish stage control and push Puff to the edge. You want Puff on the edge, or close to it. Doing so allows you to pressure her with aerial needles, while still retaining the entire stage to retreat to if she starts muscling through. You can beat her ground approach movements with needles > d-smash combos (and similar), grabs (if she blocks for the down smash), and other shenanigans. Aerial approaches are dealt with by using Sheik's awesome aerials; they win the clashes if Puff isn't spaced as a result of their speed, and by forcing Puff to approach you gain a huge edge in positioning. If she backs up, shoot her with needles.
You want to be underneath the platform, at the edge closest to the middle to the stage. This is a good position for pressuring her. In general, getting under Puff is good (with nair, bair, etc). And down smash starts being good around 30% or so. Don't down smash into her shield. If you can condition her to shield, counter it with a mix of aerials, needles, and grab. Space your grab so you max-range it, to avoid crouch-rest or evade-rest shenanigans. Spacing the grab is super crucial. Learn how far you can be from Puff with a standing grab while still being able to grab her and abuse that spacing.
For you specifically:
I watched game 2.
You're really bad at using fair effectively because it looks like you only understand it as a move that covers low. It's better than her nair for covering high if you time it correctly, so learn how to do it. Your decision to use nair and whatever for certain high approaches gets you trading hits when you could be winning. Fair is flexible, learn how to do it in a variety of ways (rising fairs, delayed fairs, etc).
Tilts are horrible against crouching characters at low percents.
Use your needle angles to control space more effectively, and swat her away with fairs when she attacks you. Basic camping strat.
You counterattack a lot when you're in a bad position or when it clearly won't work. Nair oos, shield grabs, WD oos forward to try and tilt, etc. You need to reset your position a lot against spacing characters because they're trying to stay safe by maximizing the range of their moves.
You take way too many risks against grounded Puff with dash attack, tilts, etc.
You need to refine your combo decisions. With how bad this Puff's DI is, you could easily be getting 40%+ combos on him. Tilt > SH FF fair (delay the fair as much as possible while still retaining the autocancel) > a full set of needles if they DI the tilt poorly is pretty good way to rack a lot of damage. Throwing a full set of needles at Puff after you hit her away with an aerial is a pretty good way to rack damage on her at low percents. You seem to kind of flail around with automatic f-tilts despite the opponent's trajectory or what percent they're at, etc. Pay more attention to where they're going and plan your follows accordingly.
When characters like Puff, Peach, Ganon, etc. are doing their high aerials too close, that's your cue to get under them or attack from a favourable angle with fair or whatever. You forgo a lot of chances to get a good fair positioning and do damage and instead just block and counterattack badly or other stuff like that.
General tip: I prefer recovering low to recovering high if the opponent's not on the edge and also not in a position where they can get to the edge. Sheik's Up+B snaps to the edge really well, and you don't have to worry about air-dodges being read and whatever. I guess some characters can hit you out of it, but that's what sweetspotting, invincibility, and threatening with a potential DJ fair or whatever is for.
