Çağan Mert İŞLEK ( @islekcaganmert ) asked this question at FediForum 2025 (in the comments).
The answer is — it already exists.
It is called GreatApe.
GreatApe is a conferencing platform for the Fediverse and the Social Web — where an audience can listen & watch live, and can be invited to join the speakers on the stage.
You can try an early MVP here:
With more features being added every week.
