Andrid 11 clean flash with OpenGapps Pico & Magisk 21.4.
I've spent half of Saturday setting things up again, and the only genuine problem I've seen is "DM Config Update keeps stopping". I have no idea what this does, but I've disabled it in Titanium Backup and don't think I've seen any related problems yet.
Everything seems to work fine, though I've had to spend a lot of time refining permissions to get all the apps working. The last thing I haven't so far been able to fix is Bitwarden Face Unlock, although Face Unlock itself works perfectly. If anyone is using Bitwarden (recommended password manager) and has successfully got the security option to enable biometric Face Unlock, I'd be grateful if they could tell me the secret...

hhrokarvi, thanks again, as always.