I went from a iPad Air M1 (since it was in the return 30 day period) and upgraded to the iPad Pro M2 11". (it was on sale at amazon Italy for 820 euros instead of 1060-1090 euro)
As Roon remote it doesn’t really matter much if u ask me. but if you are going to use the iPad for other stuff (Netflix etc, connecting a external monitor to it, or using it as a desktop replacement) its worth it to go with the pro. the I paid only about 120 euros more for the pro and it has 120 hz, better sound quality, that new Apple Pencil hover feature, better camera , and the iPad Air had 64gb storage and the pro has 128gb.