I've heard there's an official kbin app in very early stages. I don't know who's working on that, but it's not in the 2023 roadmap that Ernest has shared in the sidebar - and it rightfully doesn't need to be a main focus at this early stage. I know most people reading this have probably just gotten here as well, but I wouldn't be surprised if a developer out there has already started. The PWA (web app) experience isn't bad on mobile. It's no native app though. Lemmy has that going for it, and I'd love for that experience here on kbin.
I'm working on one. They have API documentation but no public access yet... so in the meantime I cooked up a simple scrapper. Just to get the basic UI up and running.
On the reddit app called Joey For Reddit they had a feature that quickly became a must have for me. It would automatically mark a post as "read" after you scrolled past it or clicked on it. The second part of this feature was a little button you could hit to hide all posts marked as "read". It constantly kept the frontpage fresh with posts I haven't seen yet. Please please please add that feature. It was the only reason Joey was the only app I could use.
There is no publicly available API for kbin yet, though it's intended. Once the lead developer has breathing room I'm sure that's still on the to-do list.
I think one of the big 3rd party developers throwing their weight behind Kbin or Lemmy right now could get a lot of attention in this news cycle. I think they've all expressed they'd rather work on other things than just shift their app to a competitor though. Which is a shame, I'm really going to miss the polish of Apollo.