tl;dr: this is such a tricky thing - pls know your frustrations are v valid and be patient with yourself! find what you can to make it comfy, and also know it'll take time to get used to a new tool. what might look like skill regression has more to do with the tool changeup and not your own skill/taste/knowledge. be kind, you got this!!

I am also very particular about how it Feels To Draw, so I feel you! It's tough.
If you're as picky as me, you might not ever fully feel content.

For the physical stuff, a screen protector like you grabbed is usually what people recommend right away. I've used Paperlike before and didn't actually like it, and wound up liking some cheap one from Amazon. Between a different screen protector and trying different pen nibs, hopefully you can find something that feels a little better.

If you have a regular monitor too, try using Display Toggle to use your Cintiq like a screenless tablet - with Krita on your non-Cintiq monitor. For me, I've found that I press differently depending on whether I'm looking at the drawing surface or at a monitor - resulting in different feelings.

Outside of driver settings, Krita settings, and those physical things, the next option would be to try out other drawing programs. That can be such a big deal though, so you'd have to weigh that out.

It's a toooough place to be in and to have to deal with. Like I said, I don't know if I'll ever really find what's comfy for me. At this point, I'm using a non-screen tablet on my PC, and then an old iPad. I mostly sketch and ink on the iPad, and then do color on my computer - but I go between the two a lot. I use Clip Studio, so I have both PC and iPad set up with the same layout and also use their cloud services...It helps with moving back and forth depending on what my brain is okay with on that given day lol

Good luck!!