Get LemmyRedirect and LinkShare (https://github.com/1fexd/LinkSheet/releases/tag/0.0.33) then make sure you either set LinkShare as the default browser or nothing as the default browser (so you get the browser pop up)
The problem is that it's a https link to another instance. Boost would need to know what the corresponding url/post would for your instance to open it properly. Jerboa has the same issue.
You'll notice if you open the link in your browser that you'll be sent to lemmy.world's website, where you aren't logged in.
Use lemmyredirect and you can shunt links to boost.
It's due to the amount of URLs Boost needs to set itself as default for. There's Lemmy Redirect which can forward them to Boost: https://github.com/zacharee/MastodonRedirect
Edit: Huh, just tried it, that didn't work either with lemmy.world
It doesn't need to set itself as the default when the link is inside the app already. It just needs to recognize a link to a Lemmy instance.
It's a pain to setup, I had to use shizuku because the other methods would crash the app.
Boost For Lemmy
Community of the Android app Boost for Lemmy