yt-dlp is relatively stable, but still occasionally breaks for long periods. I get the sense YouTube is becoming increasingly adversarial to yt-dlp as well.
I don't know the details, but it doesn't seem like yt-dlp is running the entire YouTube JS+DOM environment. Something like a real headless browser seems like it would break less often, but be much heavier weight. And Youtube might have all sorts of other mitigations against this approach.
> yt-dlp is running the entire YouTube JS+DOM environment
IIRC they maintain a minimal execution environment that is able to run just the JS needed to pass a few checks but this breaks too often enough that they're planning to make Node.js or another JS interpreter a hard requirement (possibly already happened).
It would probably help people who want to go to a concert and have a chance to beat the scalpers cornering the market on an event in 30 seconds hitting the marketplace services with 20,000 requests.
I can try to see if can bypass yt-dlp. But that is always a cat and mouse game.
To clarify - yt-dlp is a command line tool for downloading youtube videos, but it's in a constant arms race with the youtube website because they are constantly changing things in a way that blocks yt-dlp.