Upbeat Live Music App is not really live, but more like a zoom call where you can make fast collab music videos with your friends.
You start a "room" that is very similar to a zoom call. In "leader mode" one person records the rhythm track first, then the other participants record to it. When everybody finishes their recordings the app mixes them together automatically. The room owner can then play back the collab video and everybody else can watch. Chat about it. Maybe download the video. Rinse, reset and repeat.
Unfortunately "leader mode" and "backing track mode" are only available under paid plans. On the free plan you can only try "quick mode" = everybody records to a click track.
Upbeat Live tutorial video
Drunken Sailor: Another Upbeatmusicapp.com Live
Also see about Upbeat Perform https://www.djangobooks.com/forum/discussion/18205/upbeat-perform-make-music-collab-videos-online-asynchronous#latest
Hope it helps