Fn key to switch input sources stopped working [duplicate]
Solution 1:
Using Fn to switch keyboards is new with Big Sur. Buggy behavior has been reported by many users in the Apple discussion forums. Until Apple fixes it, probably best to use the traditional shortcuts found in System Preferences/Keyboard/Shortcuts.
I understand MacOS 11.2 should fix this problem when released.
Solution 2:
The traditional key combination for switching input sources, Ctrl+Space not only continues to work on my M1 MacBook Air, but using it once restores the Fn/Globe key back to also working.
As someone more or less new to the Mac because of the M1, I actually had no idea about the traditional key combo until hunting down this problem.
It's worth noting that in the preferences, it does mention Ctrl+Space but does not mention that Globe/Fn does it too. I suppose I must