Since your system works best without KMS "modeset" support you should keep it disabled using:
nvidia-drm.modeset=0 i915.modeset=0
or
nomodeset
and then "Failed to grab modeset ownership" will never happen. The log file attached in comment #53 shows nvidia-drm.modeset is incorrectly set to 1 when it should be 0.
Since your system works best without KMS "modeset" support you should keep it disabled using:
nvidia- drm.modeset= 0 i915.modeset=0
or
nomodeset
and then "Failed to grab modeset ownership" will never happen. The log file attached in comment #53 shows nvidia-drm.modeset is incorrectly set to 1 when it should be 0.