Excalidraw has not worked well for me on my 2018 iPad Pro using my Apple Pencil. The first few strokes are picked up, but it soon gets to the point where only every other stroke is detected, unless I draw/write at a snail’s pace.
I have mentioned this to the creator of the plugin, but it sounds like it’s more with the base code and not the plugin, so there may not be much that can be done for now. I’m curious if others have had the same experience on an iPad, or if it’s just me.