I installed the docker container using docker-compose and then installed Redirect in YunoHost, which allows you to map a domain (subdomain or "domain/[something]") to a port, in this case the port of SABnzbd's web ui. You can install Redirect as many times as you want btw, I've set separate subdomains for SABnzbd and qBittorrent that way. I can also give you the exact settings and docker-compose file if you want.