This is a plugin I found recently and really enjoy. It gives you the opportunity to redirect several webpages to alternatives. For example Youtube to FreeTube or Piped. If I search for youtube in Firefox, FreeTube automatically opens and shows me my feed. I like it, I use it, I can recommend it.
Ah yes, of course. If you had an actual Android TV you could install SmartTube which hides ads just like ReVanced. But I don’t think it works on a bare Chromecast