Things to try:
- Switch to intel, reboot, switch back to nvidia, reboot
- Add
Option "PrimaryGPU" "true"
inside the outputclass of /usr/share/X11/xorg.conf.d/10-nvidia.conf
- Try with the v390 driver
- check if the file /lib/modprobe.d/nvidia-kms.conf exists and change
modeset=1 to modeset=0
then run sudo update-initramfs -u