Some random tip I ran into:
wordpress pokes itself (curl?) for updates and management tasks, so it requires to be able to find itself through your public url. My NAS hosts wordpress inside a docker container through a reverse proxy, and inside the docker container it must resolve the public hostname (blog.evert.rocks) to my internal NAS ip (192.168.xx.xx). I should set up dns properly, but haven’t done so (yet). Fix this temporarily by echo “192.168.xx.xx blog.evert.rocks” >> /etc/hosts inside the docker container (vim/nano are not in the wordpress image). Of course this goes away after every restart, will update when I have a structural fix.