Ubuntu 22.04 gui freezes intermittently and permanently. Restarting gdm via ssh fixes until next time it freezes

Question

I have a Linux box, not a laptop.

Running "glxinfo -B" yields the following:

name of display: :0
display: :0  screen: 0
direct rendering: Yes
Extended renderer info (GLX_MESA_query_renderer):
    Vendor: AMD (0x1002)
    Device: AMD Radeon RX 580 Series (polaris10, LLVM 15.0.7, DRM 3.54, 6.5.0-15-generic) (0x67df)
...
etc

External HDMI monitor.

When it freezes, I SSH in and do:

sudo systemctl stop gdm

Wait a couple of seconds, then:

sudo systemctl start gdm

Then I can log back in and keep using it. Until the next time it freezes.

I tried installing the latest AMD drivers and then it just had a blackk screen; had to reinstall Ubuntu.

Would trying something else like lightdm (or ?) help?

Any ideas?