I have an iPad Air 3 covered with a Fintie case with a built in screen protector and I’m using the Apple Pencil 1 with it. I have scratched the cover using the pencil. I admit I have a bit of a heavy hand but when I was using one of my drawing apps, I was experimenting with the pencil using different angles and different pressure. Obviously I was press too hard.
Just be careful if you don’t use a screen protector. I plan on getting a new case, and I am going to buy the nib covers that lobsterghost1 is recommending.
However, a new case and the nib covers are not a priority. Dealing with life stuff is my priority right now.