I have found out Win11 needs up to date drivers which could be your issue. I went to AI piolet it said this
Bluetooth speakers typically use the same drivers across Windows 10 and Windows 11. Since Windows 11 is based on Windows 10, most existing drivers should work seamlessly. However, if you encounter issues with your Bluetooth speaker not being recognized as an audio device in Windows 11, try the following steps:
Run Troubleshooters:
Go to Settings / Update & Security / Troubleshoot.
Run the Bluetooth, Playing Audio, and Hardware and Devices troubleshooters.
Update Everything:
Disconnect unnecessary peripherals.
Update your OS, drivers, and apps to the latest versions.
Remove and Re-pair:
Open Settings > Devices.
Click on Bluetooth & devices.
Remove any existing devices from BLUETOOTH section .. and start SERVICES.MSC in Run Command .. check if below services is set to AUTOMATIC .. (ignore my MANUAL settings)
Thanks for the advice, Mickey52 and Xploit Machine. Updating all my drivers and the OS to the latest versions resolved the issue. My Bluetooth speakers are now connecting without any problems. Thanks again for your help!