I've been fighting moving over to some digital creation with part of the problem not being able to get used to the slick iPad pro cover and the Apple Pencil basically sliding over the screen.
I've tried a number of screen protectors but they were all just as slick.
After a number of months I finally found a screen protector that has a little bit of tooth to it, not quite pencil on paper feel but pretty close.
https://www.amazon.com/gp/product/B016B12TSW/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
For $10 (2-pack) it may be worth a try for anyone that does not like the slick drawing surface.