LibreTube - uses Piped as video source by default. Subscriptions and playlists can be created, all without actually interacting with YouTube.
Clipious - uses Invidious as the video source. Also allows for subscribing and accounts. Lesser known client
NewPipe - Gets the source directly from YT. Allows for subscribing and creating playlists
Additionally, there’s also ReVanced that lets you patch the regular YT app to include useful features.
Most F-Droid stuff AFAIK should be pretty plug and play. It’ll download an APK which you then just open in order to install the app. You may need a file browser app if your phone OS doesn’t come with one. You may also need to allow installs from third party somewhere in the settings. But android isn’t like iOS and won’t generally restrict your ability to install whatever you want, outside of an options popup to make sure you know what you’re doing.
I don’t use LibreTube personally and can’t speak on that specifically though, if it does something other than just download you an APK file.