The existing (M.2) wifi/bluetooth module works just fine. My issue with bluetooth on Linux is that it's never been able to pass this testcase: Use a bluetooth headset as an audio I/O device. Repeatedly over disconnects/reconnects. For the past few years, it works when you first configure it - beautifully, you can choose your codec and so on - but soon stops doing so even if unpaired and re-paired. Maybe "the year of bluetooth" on Linux has arrived and I've just not tried lately.