I evenetually trashed my whole server, reloaded Ubuntu 22.04 and decided to try the installation from source again based on the greenbone official documentation.
This worked finally and got the system running without SSL (Again, why is this even a default setup. Default i.m.o should be ssl).
After some research found the changes required for SSL, got myself a proper SSL cert and configured accordingly. everything working now as it should.
I have already tried several given solutions, but none of them worked. Can anyone help me? The service runs on the right port but does not work with HTTPS, it only runs on port 443 but in HTTP.
I wanted to comment here as I was having exact same issue as tomiking.
My solution was after running openssl command to generate cert/key to change the private key ownership on host machine to 1001:1001 from 1000:1000 because 1000 is the UID of the user of your host machine you are using but the container has user gsad with UID 1001 as seen in /etc/passwd if you exec into container.