I understand you have two options. First, your relay is like a backup of the other publics relays you are using. That is when you enter your pubkey in your Umbrel Nostr Relay. And the other option you can use is add your Relay like a Public or Private Relay. If you want that second option, you have to port forward in your router 4848 port, to get access from internet. If is just for personal use, is much better use a VPN to connect from internet.

Tell me if you have more questions.