This link only mentions what we tried already:
This thread solved the issue - but it turned out to be a hardware issue:
https://forums.linuxmint.com/viewtopic.php?t=306711&sid=7588d1360b76888ae4edd77838c60676&start=20
This blog covers that the Lenovo MIIX 320 has standing problems on Linux including Sound issues and webcam not working