You basically want a proxy-ish service that puts you all on the same network. Tailscale is a commercial option for this but there is a very good open source one called Headscale.

Headscale requires command line stuff, most importantly you need a server that all parties can reach and you need to set up the service in it remotely.

Once it is set up it does have a nice graphical web UI though.

Here is a (possibly outdated) guide using an (unsupported) docker-compose method: https://techoverflow.net/2022/01/16/how-to-setup-headscale-server-in-5-minutes-using-docker-compose/. It gives a sense for how easy the basics of getting set up are, though. You should be able to buy a cheap ($5) VM and follow the official docs and be good to go.

Keep in mind that networking is complicated and that this software essentially adds a network to your computer, so there are potential security risks. Just make sure to follow the best practices they recommend and turn off your own access whenever you aren't using it.