I ended up using duckdns for a free domain. It sucks that I had to tie it to a google account, and maybe one day this might be an area where I buy a proper domain instead.

I have a glinet Flint3 router that makes it easy to spin up Wireguard servers on it. It was a bit more finnicky, but eventually I was able to get into the advanced settings and configure the router to sync the dynamic IP with DuckDNS too.

So I have Wireguard on my phone and my wife’s phone. We have one pair of close friends who have a connection on their router too (and vice-versa) and their own Jellyfin server.