* No autoplay on playlists: https://addons.mozilla.org/fr/firefox/addon/no-playlist-auto...
* No translations and AI dubs: https://addons.mozilla.org/fr/firefox/addon/youtube-no-trans...
* No YouTube shorts: https://addons.mozilla.org/en-US/firefox/addon/hide-youtube-...
* More videos on the home page / smaller thumbnails: https://addons.mozilla.org/fr/firefox/addon/youtube-tweaks/ (to be fair, it could probably replace the "No YT shorts" one)
Not sure how safe those are, but since they only require access to data for youtube domains I assume if there was a leak it would not be too bad.