Hi @humorkritik
Do you have F-Droid installed? If this is the case it’s quite possible that you have the bug like many other F-Droid Users that can break your wifi or tethering or both.
In this case tou really should try to delete wpa_supplicant.conf and p2p_supplicant.conf (the second is for wifi tethering)
Also, I read you need tethering for your notebook? There is a usb cable tethering option which is really cool, don’t know which operating system you are using but with Ubuntu it worked out of the box.