This has been, and will probably continue to be, and ongoing issue. Google is working hard to block VPN and Data Center IPs at a network level when using their API. Usually we get patches within days when an episode like this flairs up, but some times that also triggers even more action from Google to change their methods. Usually it's an issue with the underlying libraries being used like yt-dlp, youtube.js, or invidious API; meaning all YT circumvention apps get affected at the same time (e.g., FreeTube uses Invidious API).
Constant cat and mouse game. I usually try FreeTube first, if that fails I'll try 2 Invidious instances that usually work well (one self-hosted, the other inv.nadeko.net), then I try Grayjay, and failing all of that I'm just not watching the video right now.
ETA: nadeko added a note about it to the top of their site, so FT is definitely broken because of Invidious/Google
Their note:
Youtube changed something again, so if a video does not play, it's because of that.
ETA2: lmao, another public invidious instance shows this and doesn't even load the app:
Maintenance. Invidious broke completely. Come back later.