You can use a phone as a speaker and microphone for a Windows 11/10 PC with a free app called AudioRelay. Learn how to set it up!
If Bluetooth driver is missing or gets removed after a Windows Update, add the legacy driver from the Device Manager, install the correct driver from your manufacturer, etc.
When your Bluetooth mouse suddenly stops working and the entire Bluetooth functionality disappears from your PC, no toggle switch, no Bluetooth in Device Manager, it usually indicates a deeper issue ...