I have seen this question Record video with external bluetooth mic (ie headset) posted 8 years back and app solutions do exist but not with Android 10,so it's not a duplicate of this question or other questions which suggest apps (they don't work for me)
I am helping my wife record instructional videos on OnePlus 7, running stock Android 10 (not rooted).
I want to use Bluetooth audio input instead of the device mic, as it would provide better flexibility.
I don't find any settings to enable Bluetooth in camera or elsewhere and internet search hasn't helped.
Blogs recommend apps but surprisingly none seem to work reliably with Android 10. BTmono works sometimes and is not a reliable solution, and similar story with Camera fv5
Any suggestions, including apps,
accessories are welcome except
Separately recording audio and sync with video, that's too much work
Involving signal processing hardware
Accessories like mic (I have asked for accessory advice on SE.Video Production and hope to get better answers there)