Comment 1 for bug 2039701

> Was able to reboot with strg+alt+F(x) sudo reboot

Once this happens again, can you please collect dmesg and journalctl (some hundreds of lines are probably enough) before rebooting?

Instead of launching Chromium normally, use

  chromium --enable-logging=stderr > chromium.log 2>&1

Also:

  snap connections chromium
  snap info chromium

> via gürgelschnüffel:
>
> vainfo

First the most important question: What is Gürgelschnüffel?

Now, running vainfo in your host system doesn't help much, because Chromium is supposed to use the driver provided by the (not ideally named, I know) Gnome snap, /snap/gnome-42-2204/current/usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so.