The zap stream servers seem to be the bottleneck. It studders when using phone camera and desktop webcam but without video it seems fine. I have seen other users try to irl and have issues.
According to chatgpt video takes up a lot of bandwidth and that's probably the cause of the issue. I'm not sure if zap stream is only a dedicated or vps but their host is called lnvps.
I downloaded your app and it seems you are using zap streams severs which is probably why that happens on your app too. There is no way to change the stream servers I'm guessing you don't have your own stream sever.
You could setup your own shosho servers or wait until the zap stream developer solves the issue.
I might setup my own stream sever in the future to bypass for testing but I'm not an IRL streamer so zap stream severs work for me since I don't use webcam.
You app is interesting. I'll keep playing with it.