As the link you sent me discusses, wasapi shared in cakewalk is the preferred option since it allow multiple sources simultaneously. However, this is when the popping occurs, but only on the MODX USB audio output. Anything else attached at the same time does not pop. Midi does not pop, USB mic does not pop.

When I switch to ASIO in cakewalk, I get no popping but can't use multiple USB audio sources, and for monitoring I have to listen through my MODX headphones.

I also encountered the same popping in audacity DAW, same sound, same randomness of frequency.

The only time I don't encounter the popping (which sounds quite a bit like the popping you hear when someone is fidding with a jack input, but quieter) is when the ASIO driver is the only one involved. However, this limits me to the MODX as the only non-midi input when using a DAW for recording/etc. purposes.

This is why the only solution I've read so far that seems likely effective is to sidestep the issue by using a digital USB interface for all audio inputs instead.