I used UAD on my S21 and it’s been fine. You can’t actually uninstall the unwanted packages but at least you can disable them. Can’t say I’ve noticed any particular improvement in performance, buts it’s nice to know that my phone isn’t running a bunch of unnecessary services.

Be careful disabling Bixby if you intend to use features like Samsung Routines, though. I seem to recall doing that and breaking functionality, so I just went back and re-enabled it.