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 had made a long ramble about how it's not saving between sessions, likely because of my own privacy settings, but then I realized I was making an argument for changing my privacy settings if I'm okay with an app staying signed in. I guess maybe I just prefer the self-containment aspect?