Update: after 3h of constant debugging and trying to fix the master pgp keys (one key was always expired and Blahaj couldnt recreate them) she gave up an is now installing Opensuse instead.

Second Update: after realising, that either I Am stupid, or the OpenSuse Tumbleweed install screen is complete bullshit I found something called ArtiX, that ended up working completely fine and actually worked. That was one hell of a trip.