Big Sur "Upgrade" with Xerox Workcentre 6515

Just this past week I upgraded my 2017 iMac and 2019 MBP from Mojave to Big Sur, which now appears to have been a big mistake. I now have issues with NordVPN which doesn't seem to want to run on my iMac (disconnects) and my Xerox Workcentre 6515 multifunction printer - it constantly looses connectivity. In spite of repeated deletions and reinstallations of the Xerox drivers I just can't get it to work consistently (more than once or twice after a reinstallation)

I've found some general information about VPN's having problems under Big Sur but nothing specific from NordVPN. In the case of Xerox on the Printerbase website there is specific information about Big Sur not working with Xerox 6515 but is stating that drivers will be available for this product. Xerox hasn't released a new driver for this printer since October 16, 2020 and the information given on Printerbase is from this month (February 2021) so it would seem it might still be some time before there is a solution.

Unfortunately, I don't have time for messing around with connectivity issues. I would like to roll back to Mojave if that is possible without having to do a complete clean reinstallation so I can get some work done instead of wasting time with Big Sur which is about as unpleasant as a dumpster fire. I would appreciate any suggestions on rolling back.