Sorry for the issues and that I’m not going to have a great answer on this one. Thank you first for posting the output.log, would it be possible to see the vnc.log from the session as well?
I’ve seen some variations around this now with Rocky 8 and the compute nodes having issues with the desktops. Unfortunately all we have are some other similar posts for users facing this:
So far it looks like for various users the key has been either to roll back to CentOS7 or to debug further and figure out the correct packages needed.
This is something we have on our radar to look into more when time allows as you can see from the last post. Sorry I don’t have a better answer at the moment for you though, but the vnc.log would be nice to see to try and replicate on my end.