I would recommend to make sure your ports are actually open, there are many online port scanners. You would want to set No-IP with your router IPv6 address. When scanning you would want to put the No-IP address you configured or the router IPv6 address.
I would highly recommend to not disable the firewall on your router but to port forward the ports you need (80/443) in your case.
If you are able to ping the No-IP address, and it gets resolved to your router address than its working.
Rare_Lead241 covered the most common and feature full stack (plex/jellyfin + *arr stack). Another option It is not self hosted but, it might be worth looking in to stremio + real-debrid in this use case.
You will find plenty information about it online including Reddit.