@newqubesosuser canyou try, in that new fresh qube, installing VLC and then attaching the webcam to the Qube, then using /dev/video0 as input/capture in VLC.
does it look OK ?
Can you also check out the media/codec in that same running VLC and see whats showing for frame rate, display resolution and any dropped frame count
Basically what we are trying to ascertain is there a bottleneck on the USB input to the Qube, or / as well as a misconfig in V4L2 input.
Personally, my bet is on a “problem” in Firefox ESR running google meet (eg, deploy chromium in a Qube and see what happens then)