https://immers.space is an ActivityPub-based virtual meetup space that I’m working on. It’s based on the cross-platform 3D hangout space from Mozilla: Hubs. I’m working with the Mozilla Hubs rc3 assembly to use Immers Space for their event, and, if the AP rc3 used it as well, the two events would be federated!
Map making is a bit more involved for 3D, but there is an in-browser editor (and lots of remixable existing content).