So a bit more data. Mounting encrypted drives takes *forever*, and is substantially longer than unencrypted ones. For ones in the keychain, it's a bit faster, but if you have to enter the password, that screen stays up (and disabled) for 15-30 seconds per drive.
Enumeration takes vastly longer than my intel/2019. Like seconds for that one and multiple minutes for the M1 Max. I can't sure sure if it's an M1 or Monterey issue, but I don't recall the delays with 12.0, just with 12.0.1 (and 12.1 doesn't fix it).
The one thing I simply cannot do is erase/format a USB drive. It just never completes. Taking the failed drive to an older intel machine erases in a few seconds.
There is absolutely something wrong with the USB subsystem. Hope to heck it's not hardware....