Hmm… bluntly, a lot of games struggle to hit their target framerate on the Switch as is. I’m not sure there’s available overhead to implement streaming. At the very least, I’ve not heard of anything either!
If you don’t want to buy a capture card, but have a PC, the easiest way may be to dump your games and run them on an emulator like Yuzu, so you can stream from the PC.
Asahi Linux is a project to get Linux running on M-series macs, which has taken a bunch of difficult reverse engineering, since Apple doesn’t really provide public documentation on how they work.
Running Linux means they can run steam games like a Linux machine. This is a pretty impressive landmark in terms of their OpenGL rendering support.