Anyone who’s been using privacy-respecting frontends for some time will recognise Piped. A YouTube frontend with no ads, integrated SponsorBlock, return dislikes, and a customisable UI.
Piped also allows you to subscribe to as many channels as you want without ever logging into a Google account. You can export your subs list from YouTube and import them to Piped seamlessly.
If you’ve never heard of it, give it a glance at https://piped.video. For more instances, check here.
Piped (and similar projects like NewPipe, Invidious, and FreeTube) scrape YouTube instead of using an API; so just like Nitter, they won’t be affected by a paid API.
Invidious does use a YouTube API. FreeTube uses Invidious, so probably same story there. I don’t know about the others.
I recently had a back and forth with one of invidious’s developers. Judge for yourself.
Ironically Nitter stopped working lately, since Twitter started requiring users to be logged in to read anything.