Hey, I thought I could help but the time didn’t work for me (my vote was the one for Sun), hope it went well.
There is one person, Joseph, who recently joined our OHN community call and shared a modified jitsi server he is running, I thought it might be interesting option for you.
It allows for internal breakout rooms when people can talk to each other without hearing other rooms or hearing them at reduced volume.
Below is a screenshot from our call with 2 rooms, each person can regulate each room’s volume individually and independently from other rooms.
You can write to him @jfinn:matrix.org