@maegul I think you are missing the point. I can't find a button or URL in the Lemmy interface that lets me boost something to my Mastodon feed (on hachyderm.io).
Also, it isn't easy to find toot that "matches" a post (or comment) when I'm in the Mastodon interface, even when federation has distributed it to my Mastodon instance.
Yes, once I've gone through copy-paste plus manual search process, to find the right toot, then all I have to do is hit boost, but that final step isn't the problem.