I checked both models listed in this post, the B215 page for Big Sur is working, and the Phaser 6000 doesn't have Big Sur listed as an option. Where you looking at a different product?
The Big Sur driver is now available on our driver and downloads page for your device.
I recently bought an B215 printer and soon after had to upgrade to Mac OS Big Sur (directed by my emplyer) and I know find i can no longer print anything. I tried a re-install but the install package just gives an error. I found the xerox big sur page which said B215 is 'level 3' i.e unclear if/when a big sur driver will be produced. This is a major issue for me so I am trying to find out if it will be resolved anytime soon or if i need to sell th eprinetr and buy one that has a better level of OS support like HP.
If there is any kind of workaround then please advise