On FireFox Beta/Nightly and more privacy-focused forks, like Mull and Fennec, you can enable 'Custom Add-on collection'.
You can enable it by going to Settings > About > and tapping the logo 3(?) times.
You can add your iwn account, or any shared 'collection'.
I find Redirector more useful than the other options, because you're not limited, and can add any site you want.
GL.
AFAIK, adding a custom 'collection' is the only way to add custom add-on RN (or downloading browser like IceRaven, that simply does it for you).
Neat, I had no idea that IceRaven had a custom collection built in. I stopped using IceRaven after I had discovered Mull. Perhaps I should give it another shot.
On Libretube you can select if share an Youtube link or an Piped link.
You can press the share button and select newpipe to play it.
You can install Libretube and make it the default handler for youtube and many public piped domains. This way when you click on a yt link it opens in Libretube and plays the video via your piped instance.
On my phone it's in the system settings for the app under "Open by default".
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