New nvidia gpu and now login loop

I have a desktop running Mate 20.04, grub version is 2.04. It is an AMD system with 2 nvme M.2s, 2 SSDs, a 3700x, x570 board, 2 screens, a new rtx3050 and has 2 user profiles.

The 3050 is to replace a 750ti, however I am having problems getting it to work. I have found the nvidia-driver-510 (propriety, tested) gets me graphics on both screens but I am then faced with a login loop.

I tried the recovery mode screen and found that the current version (linux 5.13.0-35-generic) just went to the login page as expected.
The earlier version (linux 5.13.0-30-generic) login worked (with those huge icons) so I created a test new user and restarted. Unfortunately although the new user is now on the login screen, all login attempts result in the same login loop.

I have also confirmed that .Xauthority and /tmp permissions are set to the user (not root).

Any assistance with this login loop would be appreciated

My suggestion is to revert the graphics to nouveau driver, reboot, then you can install the appropriate nvidia driver. Swapping cards on the fly never worked for me. I always take it back to nouveau, reboot, and then install nvidia driver for the new gpu.

Thanks for the reply and the usefull suggestion