On accessing Youtube: I’ve been using FreeTube for years and it’s great, it even has support for Sponsorblock, and your subscriptions are stored offline in the app, among other benefits. For the browser, there is also the Libredirect extension, which you can use to easily redirect to Piped or Invidious instances.
If you manage to get yt-dlp to work (btw check that you have the latest version), I’ve also used the “play with MPV” Firefox extension in the past.
I haven’t tried it, but I’m pretty sure I remember seeing a decky loader plugin for it!