Is this an alternative to Bambuser?

Hi all,
I’m embarrassed to ask such a silly question but I hired a team to work on an app that will allow people to create live classes and others will be able to join the classes and watch live.

The team suggested using Bambuser. However, it’s way above my price range. While searching the internet, I found Ant Media and Jitsi. Are these alternatives to Bambuser? Can they be used to broadcast a class to 10s of users? How does a server fit into this?
The app is created with React Native. We are already implementing video chat via node.js.
I want to understand as much as possible before discussing it with the team.

Thanks in advance!!!