I sketch a lot on the iPad pro (I used a 1st gen, 2gen and 2020, all 12.9"), and my biggest problem in every one of them has not been the amount of 'gliding', which in itself is something my brain can adjust to after a while, but the inconsistency of the naked glass due to fingerprints: they create areas where the amount of friction varies a lot, and that throws off my 'brain-hand' coordination and makes it an unpleasant experience.
Matte screen protectors are a no go for me: tried a bunch and the rainbow effect is unbearable.
I end up using so called 'crystal-hd' screen protectors: they're not matte but highly transparent ones, so there's no change in the amount of gliding (I'd say maybe they're even more 'slippery' than the naked glass), but the big advantage is that for some reason they take fingerprints much better, so the amount (or lack of) friction is way more uniform across the whole screen. I have the impression they dim the screen a bit, but I don't think there's a big change in color perception. Plus, if you do serious color correction you can calibrate it once it's applied and that's it.
Another option, which I've never tried, are the removable screen protectors (I believe moxie makes one), which can be taken off and reapplied (allegedly) very easily. So you can put it on for sketching and take it off for everything else.
