Thats hilarious, I have a very similar website tracking whether or not its one of my close friend's birthday's as he used to have like 5 different birthdays listed across social networks which was confusing.
The parallax on the constellations is something I had never considered before and is awesome to see interactive like this. Makes you wonder if alien planets would come up with their own.
I jailbroke my kindle a while back and was super excited to do it, but then didn't really do anything past that. Besides de-amazoning it, I found no real value nor supplemental features that were actually worth while. That being said, I don't regret doing it, just kind of wish there was more.
Being able to make apps like these so quickly with AI now has actually let me learn more than anything. I agree that most are not worth sharing, but as primarily C# developer, I've been making it a point to try out different languages that I would have otherwise never have touched like Rust and Go.
That being said, I think with enough polish and a little bit of passion like this Slumber app, they do become worth sharing.
I'm in the exact same boat. Look up the BeepBerry. It has the same blackberry like design but uses a Raspberry Pi Zero instead so it actually runs linux. Too bad they're no longer made but you could probably find one second hand with enough digging. For now I just use Termius on my phone but a dedicated device sounds awesome.