So the issue is that YouTube’s bot detection flags the traffic since it sees a ton of downloads at once from an not-logged-in-user.
Vrchat uses a custom version of YT-DLP that doesn’t allow you to pass cookies to it - simply replacing YT-DLP after the game is already running (as the game does a version check on the file at startup) with the official version of YT-DLP lets you use your browsers login cookies
I made an app that does this automatically when you launch the game, you can find it over here :3