I was reading Big no on Big Sur: Mullvad disallows Apple apps to bypass firewall.
This needs to be fact checked, but I don’t think I will update to Big Sur anytime soon
It’s worth nothing that Big Sur and its predecessors are built to assume that they can talk to Apple at any time, but when we don’t allow it, a few unwanted side effects pop up. For example, the keyboard sometimes takes longer to wake up from sleep mode.