YSK: a few ways to watch YouTube videos without using youtube.com
Invidious: an alternative front-end that is open-source and privacy-respecting. Here are a list of open instances. If you are reasonably familiar with docker/self-hosting you can also host it yourself, but be aware it's somewhat resource- and maintenance-heavy.
yt-dlp: this is a nice command-line program that allows you to download YouTube videos by link; also works with Peertube links. For Windows/Mac users apparently the program is available as well, but please follow their instructions. If you also have mpv installed, you can call mpv <http://youtube.link> to directly stream a video.
NewPipe: this app on F-droid.org allows you to watch YouTube videos (and Soundcloud/Bandcamp but somewhat glitchy) with an experience very much akin to the YouTube app itself.
There is also Piped, which is like Invidious.
On Android you can use LibreTube which uses Piped as its backend, so you never connect directly to YouTube.
Good list, but just want to add my 2 cents about invidious. Ive been having a hard time with their instances lately... May be related to Google trying to shut them down, but I dont know for sure. The video player refuses to load, no matter which instance I select.
Could just be a me problem, but worth keeping in mind if others face similar issues. Ive been having much better luck with Peertube instances lately.
It's definitely not a you problem. Invidious, yt-dlp, and Piped all had some serious issues just a few weeks back, I wouldn't be surprised if YouTube is secretly planning something... hence the more options the merrier. Obviously some creators are on Peertube which seems like will last longer at this rate...
I'm using SmartTube on my TvBox and live in fear it will stop working xD
There's also a component for foobar2000 (yes, I'm GenX) called Youtube Source. You can search content, add results to foobar playlists and see the video (embedded in the skin or on a different window). Sometimes the video doesn't load but restarting foobar it's usually enough.