You're almost certainly right, as far as I can tell it should be fine with Wayland and 21.04 but I am just tired of reinstalling my OS every 6 months and don't trust direct upgrades much since they lose me even more time diagnosing an issue in the cases where they do break something.
I've upgraded a few of my systems from 20.04 to 21.04 without an issue. If you take a btrfs snapshot before upgrading, you can roll back the changes if it turns out there's an issue with them.
