Speaking of ddclient, maybe check supported DNS services: https://github.com/ddclient/ddclient I don't think it's a good measure of quality, but if someone bothered extending ddclient for their service, it's probably not that bad. Plus if you ever find yourself wanting to use ddclient, it's nice having your provider supported. (NetCup is not supported, which is why I have to run an extra service on my Linux box instead of simply using the OpnSense).