Bluetooth

Would help to know what type of Mac you have, some BT settings are stored in NVRAM which can be reset on Intel Macs (reboot with command-option-P-R keys pressed) and is tested on M1/M2 Macs when cold booting (not a restart, but rather shut down, wait a few seconds, then start up).

Boot in Safe Mode and see if it's there:

How to use safe mode on your Mac - Apple Support

If that doesn't work, you may need to reinstall MacOS.

How to reinstall macOS - Apple Support

Have you restarted? Sometimes a simple restart will put things right.