I didn't install any Apple drivers, just paired and connected them in the Windows settings. I also tried a couple of cheaper Bluetooth headsets and they worked equally well. None of them would connect as headsets in Ubuntu 20.04.

I have a short bluetooth pairing troubleshooting content for RPi [1] which shows the basic bluetoothctl commands, Give it an attempt next time.

But manufacturers do test their devices with Windows Bluetooth stack (incl. Apple) as after all they hold the majority market share.

[1] https://abishekmuthian.com/fixing-bluetooth-issues-on-raspbe...