I've been working for the past week on a new kbin app. At the moment, it's just a prototype and only the "Feed" view has content (you can't sign into an account or post anything yet); you can see threads, thread images, thread comments, thread links, and thread votes/boosts. You can also change the "Theme Mode" and "Instance Host" in the settings.
Here's a link to the source code (contributions welcome for those that know flutter): github.com/jwr1/interstellar.
For testers, here are links to the first working builds: AppImage and APK.