I've clicked through all the options in the settings and no matter what I click I can't seem to get YouTube videos to play in the boost app. Every time I click on one it opens my YouTube app and I don't know how to get that to stop happening. I'm on a galaxy s22 ultra if that helps.
You need to change:
Settings -> Apps -> Boost -> Open By Default -> Add Link
In that list box, you can pick all YouTube links and select that they should open with Boost. May work, haven't tried with Boost, just with Newpipe.
Ok I got it working using this method but instead of adding youtube to boost I instead went to YouTube and unslected all its links.
Very good. :)
Just tried that and there is no option to add a site to that list.