Have you tried turning it off and back on again? JK (kinda)
Try unplugging/reconnecting the USB to see if it (UHK) comes back on. Another potential workaround could be to use the reboot macro. Idk if the UHK60 would be able to trigger macros while it’s in that state or not, but it’s worth a shot…
Anyway, it sounds like it’s probably a known issue:
It seems like the firmware update may have affected how the keyboard handles USB wake signals. Some external keyboards stop sending the proper signal to macOS after updates. Testing the keyboard on another system or trying a different USB port could help narrow it down.