I’d like to host lemmy on my LAN and I’d be the only user, no registration open. I would subscribe to communities on other instances and my instance would get the posts and comments. would that work? I don’t need it to be accessible from the internet.
Well, you can’t get updates from other instances without it being connected to the internet and reachable. So for your usecase you do need it connected to the internet. On the LAN you will only be able to see other instances on the same LAN.