I second that it sounds like HLS/DASH (Adaptive live streaming over HTTP) is what you're looking for, instead of RTP/RTMP.

WebRTC being a more open model for real-time streaming, but nowhere near as easy or scalable HTTP-based streaming today.

However we can all also start getting excited about MoQ [1][2].

[1] https://moq.dev/

[2] https://www.youtube.com/watch?v=BluV8WBGnHY