I had some issues with Sabznd write problems all of a sudden so I decided to stop the array and reboot. Now, all the disk are gone (including the internal NVME and the USB flash drive with Unraid itself), but I can access the web UI without issues (I just can't really do anything).
I also tried tools -> new config, but no luck.
Unfortunately I'm on holidays, so I can't physically access the devices (and I can't watch any of my shows due to this either).