Like there is the Official Mastodon app for Mastodon, and Element app for Matrix, which app is considered the most official lemmy app for Android [possibly also for ios]
Or atleast, the app which supports most(if not all) the features available in Lemmy
“A bit buggy” is quite the understatement. Elemental things like editing text in the input box (like deleting words or characters that are mistyped) cause completely unexpected things to happen to the text. I would not call it usable by a long shot.
I use it for 80% of my lemmy browsing, posting and commenting.
I’d call it unfinished, but definitely usable.