I was stupid enough not to dig into the logs myself, which I did immediately after creating the incident.
To people who also happen to have this problem since 2 days and use Arch Linux, this was the solution:
# sudo echo "1" > /proc/sys/kernel/unprivileged_userns_clone
After this steam is working again as normal.
Nothing extracted yet.
Your system information
Please describe your issue in as much detail as possible:
Regardless of which option I use to start Steam, I have been getting the error message for several days that has been reported frequently in various incidents: "Steamwebhelper is not responding".
-cef-disable-gpuor-vguidoes not fix this.Steps for reproducing this issue:
steam