Okay. Final message.
I finally got root cause with my WSJT-x / M1-Mac / FT-818 connectivity saga.
The final issue was resolved after a conversation with Apple support. The solution was the "(almost) if all else fails" path of creating a new user on my Mac to eliminate everything that loaded prior to loading WSJT-x because audio was getting to my Mac but not to the WSJT-x application. This worked.
One of the other applications in my main account on the Mac has somehow "messed with" the USB driver/audio path so that WSJT-x alone does not see USB audio. Once this was determined, I retested with my USB2/3 to USB-C hubs and all works fine. I don't which app is to blame, but I don't need to know if I simply use a second account on the Mac for "field "operations" which is actually a great idea!
Wow - how cools is that?
Thanks for reading if you actually did.
-- Scott, W1MVY