If you ever watch Invidious on clearnet, Freetube might be useful (I don't know if it works over Tor). It uses Invidious, and it will proxy subscriptions without signup. It's in beta, and there are some aggravations, but I think sometimes it comes from problems with the invidious instances.

The privacy-redirect FF add-on (for clearnet) will direct YT links to Invidious (or auto-open them in Freetube). I use the first one because the layout of search results seems a little better in Invidious, but I still use Freetube more, due to the single-click subscription proxies that you can group into folders. Currently, comments won't display in Freetube. Also, you can't comment from a proxied subscription (naturally).

Also, Piped proxies YT videos. https://piped.kavin.rocks/ It appends long search results and large channels at the "end-of-page". Sometimes a search-on-page for keywords will find desired vids quicker than paging through invidious. I also dropped a piped address(es) in freetube, and it seemed to work. I didn't check if it somehow just resolved to an invidious instance.