UR-RT2 No longer working following Bigsur update, even after reinstall drivers

UR-RT2 No longer working following Bigsur update, even after reinstall drivers.
I’ve just spent my day (at considerable cost) trying to uninstall and re-install drivers (3.0.5) to get my UR-RT2 working. It appears in sound preferences and audio devices but will not play audio.
Many support pages and links take me to “maintenance” or are showing 401 errors.
Hey Steinberg, help! I’m losing money!!!