Probably too far-fetched, but curious anyway since this would make things a lot easier.
Recently got a modded Switch with a chip and it’s got custom software with this Tinfoil app on it, and I was wondering if it could be possible to somehow stream to Twitch/YouTube directly, without a capture card, using an app that would work only with a modded version of the console.
I don’t think that what you want exists. The best I can offer is SysDVR, which streams video to a PC and from there you could livestream that.
Alternatively, you could try your luck asking on GBAtemp and see what they know.