GDM doesn't start automatically, only shows blinking cursor

I was having some behavior on my ThinkPad; it was having issues opening some programs. Of course I rebooted it.

However now it will not go back into GDM. I get a text based login, and can log in to get a fully functioning session. Running sudo systemctl start gdm opens a blank black screen with a blinking cursor. I can type anything here but nothing happens.

The most similar problem I found is this post

I followed all the steps, including uninstalling the proprietary Nvidia drivers. No dice, behavior is the same.

Where should I start looking for the cause here? swupd diagnose found some hash mismatches in libGL, but running swupd repair also didn’t change the behavior after rebooting.

Check the NVIDIA related threads, they contain some information on how to troubleshoot and/or uninstall NVIDIA drivers properly.

I did already uninstall the Nvidia drivers.