There is no realtime interaction on stream anyway if you have more than a handful active chatter. And lag is high by default if the streamer is doing more than just chatting, like playing a game, building some stoff or reacting to a video.
I don't think you know just how low latency WebRTC is.
CPU usage on the streaming PC does not increase latency unless the PC is severely under spec. CPU usage increases CPU usage. That's it. Encoding usually happens on a GPU, and scene composition happens on the CPU, which is either a zero-copy routine or a very fast memcpy.
My point is that from what you're saying, it seems clear to me that you are not aware of just how good WebRTC is at this kind of thing.
So which experince are you talking about?