Another user just reported running into the exact same issue, an XID 62 followed by XID 16 and Xorg slowdown:
https://forums.developer.nvidia.com/t/510-515-drivers-throw-xid-62-16-with-certain-nvreg-registrydwords-set/217009
While you don’t have any registry dword set and also mentioned that the 470 driver didn’t work either, maybe something can be found both system have in common.