Driver 470.103.01 - gdm-x-session Can't Start Prime-Offload-permission denied eror-then screen freeze

Ubuntu 20.04 system is having system freezes 6-10 times daily.

A frequent theme is logged messages such as:

12<1>Apr 24 11:15:46 | user.warning | greystone | PN= | ST=/usr/lib/gdm3/gdm-x-session[307]: | AN=- | MSG= /usr/bin/prime-supported: 38: cannot create /var/log/prime-supported.log: Permission denied
12<1>Apr 24 11:15:46 | user.warning | greystone | PN= | ST=/usr/lib/gdm3/gdm-x-session[307]: | AN=- | MSG= /sbin/prime-offload: 29: cannot create /var/log/prime-offload.log: Permission denied

In addition, lsmod indicates that nvidiafb is not compiled into the module.

GRUB boot commands include:nvidia-drm.modeset=1 nouveau.modeset=0

I have not been able to otherwise isolate the specific cause of the freezes lately–a few weeks ago, they were xorg hard locking one core at 100%, but not lately.

Still, these seem nevertheless to indicate a failure to offload graphics processing.

There also may be some involvement of audio processors, as reflected in my post yesterday, with gnome-shell or its components launching two volume controls and then pulseaudio somehow getting triggered into configuration and playback reset loops.

Any thoughts about how to resolve this would be most welcome.