In both instances it would probably be best to use a format like GLTF (webGL).
There is a gltf export.
GLTF is what the oculous and steam home environments are.
no interactivity, only models, tex, and anims, and sound.
its limited.
I don’t think you can “render it on the server”
unless you just make it pcvr and use airlink or Steam streaming.
it is severely limited though.
It would be fine for simple environments tho
another way is to render 360’ panoramas from several points and then they just navigate through the panorama
but if you want them to “walk around and look freely” you would need to use web gl or streaming, or just give them a link to the 500 meg walthrough exe, which would be the highest quality.
The other way would be to make the environments into VR Chat rooms.
But that’s unity not unreal.