I have experienced two issues:
MacOS in no way informed me of an update to Xcode. I only found out whilst updating (through brew) some of the packages that needed the lasted version of Xcode (i.e. 12.4).
What I don't understand is why does 12.4 need over 11GB of disk space for an update to 12.3? If I have missed something simple this update is a minor and not a major change so why does it need so much space? Working on a MBA (MacBook Air (13-inch, Early 2015)) I'm already fighting disk space because of issues upgrading to Big Sur (v11.2) (especially to Photos).