Bluetooth not working on MacBook Pro 2019, Big Sur OS

I have had intermittent issues with my bluetooth over the past year. When I first bought the Macbook, there were no connectivity issues at all.

Then sparingly it would forget an already connected device, forcing me to repair. Next it started not even bringing up the devices as an option.

Most recently I purchased some Airpod Pro's...surely these would connect being an Apple device, but even these weren't recognised.

I have reset the bluetooth module and PRAM'd the Mac as per a friend's suggestion, and while this worked once in the past, this is no longer working even after trying on several separate occasions. I have also run Apple Diagnostics and it came back with no issues at all.

Everything else is working perfectly and it is practically the newest model with the latest software...what can I do?!