Does it bog down with more than 5? For it to be a serious alternative, it needs to support meetings with dozens of participants (even if it requires beefy hardware).
It fares pretty good in my opinion, I was taking Japanese classes before this COVID situation and they implemented remote classes using a self-hosted jitsi instace, we're 15 people in the jitsi room, we have the class for 5 hours and it's pretty stable, I imagine there are more rooms working simultaneously too, since we were not the only class taking place before this.
Jitsi works great for me with 20 participants, never tried more.
Unfortunately yes, I mean, the software allows for thousands of participants but the stream would be terrible. For 5-50 people, use BigBlueButton instead.
The scaling of bandwidth with the number of people _actually transmitting video_ is not perfect, so you results will vary with internet uplink speeds.