Hello,
In my case I held events for up to 130 people, on a PC I put my user to share screen, when it exceeds 50 people a room is created with the new people, then I access it from another PC with another user and I give them host permission and I share the screen in that room 2, if a guest number 101 accesses, from a third PC I add another administrator and share the screen.
It is laborious, but it is the only alternative. The bad thing is that you cannot manage users by rooms and often the first room is left with 5-8 users, as they leave, but there is no longer the option to unify the rooms. It is common for people to detect many users in a Spatial world and enter to see what is happening, but they often leave the world and their space already occupies a place of 50.
The only thing is that if they share the 3 rooms in the chat, they see it at the same time.