Hmmm. That's an interesting idea, especially since OBS has a built-in "transparent" browser that I use to do lower thirds. Getting it to render sequences/chunks of Markdown doesn't seem too far-fetched at all.
Spend some time setting up OBS and then control it via an Elgato Stream Deck. Really nice way to do pre-scripted things via easy buttons.
OBS already has a virtual webcam mode, fyi
Yep, and you can prepare a list of scenes that more or less replicates the "script" feature here (though you can't save the "list of scenes" separately).
I have a YouTube video from a couple of years ago where I show how to do this sort of thing in OBS. So yeah, it's possible!