Kbin was a fantastic project and its developer deserves all our respect.
Unfortunately Kbin suffered a perfect storm that overwhelmed him: -he was born at the wrong time; indeed: he was born at a very right time! That is, just before migration from Reddit reached its peak
it was too immature and too good at the same time: users saw how good it was and dived into it en masse
as if that wasn’t enough, even more users flocked to Kbin due to a well-known Fediverse popularizer, blinded by ideological hatred towards the Lemmy developers, who recommended it to everyone as the best alternative to Reddit, saying something lie: immature software like Kbin CAN NEVER be a better alternative than mature software like Lemmy (oh yes, congratulations FediTips: you actively contributed to sinking the Kbin boat!)
the developer was alone, a very normal circumstance for a project in development; but this led to an absurd overload and a totally destabilizing overexposure!
finally, the usual dynamic of free software has struck again: herds and herds of ignorant, selfish, resentful people lacking any empathy began to DEMAND improvements, modifications and corrections to a software that (I repeat once again) was still immature, without giving ANYTHING, and when I say NOTHING I mean without financing the project.
I completely understand that the developer went into burnout! The meltdown of lone developers is a very frequent phenomenon in free software… These pressures are almost impossible to bear: to bear them you need to have balls of steel, decent financial resources, many true friends and a pathological level of enthusiasm and self-esteem to resist such strong emotional pressure.