if you look @ About this Mac, by clicking on the Apple Logo in the top left of your screen, and choose System Report. Near the bottom of the report under USB... you should see something like this if the Ant+ Stick is good.
To answer your question it is an M1, however I have been messing about on my machine and dumped 3.5 and went back to 3.6 build 4007 (August 14 2021)and now for some reason it works. I havn't done anything differently just dumped 3.5 to the bin and installed 3.6. As it hasn't been signed I had to bypass the check in Security & Privacy but, the ANT+ dongle is now recognised by GC and I can assiciate my ANT devices.
Happy to supply more info if needed by the devs.