I'm considering getting an iPad (upgrading from . . no iPad) and seems like the 10th gen is really awkwardly placed between the 9th gen and the M1 Air. If I want basic and cheap, obviously go 9. If I want powerful and am willing to pay for it, the Air is a LOT better than the 10 (much faster, better screen, more capable, more accessories), and with the Air on sale for $519 at Amazon, it's a much smaller jump in price from 10 to Air than 9 to 10.
10 looks very nice but seems to give you the worst aspects of the other two and I'm confident I'd regret not just going higher or lower.