Hello,
I’ve been experiencing this same thing.
RTX GeForce 2080 Ti
Ryzen 3900X
Ubuntu 19.10
nvidia-driver-435/eoan,now
Every couple days I’ll get the Xid 61 error and need to do a hard reboot. I’ve disabled all of the gnome extensions and have also set __GL_MaxFramesAllowed=1 as was mentioned, but to no avail.