Your Phone Companion Bluetooth Device Issue

Running MS "Your Phone" on the Windows desktop, and "Companion" on my Android S10.

All functions work with the exception of handing over calls to the phone and maintaining BT earbud connection. When the call hands-over to the phone, it defaults to the phone's audio, not the connected BT device. This applies to all BT earbuds and earphones I've tried.

Samsung support has no idea, telling me about incompatibility issues between Android and Windows, yet Samsung are promoting the connect to Windows as a feature.