Oh, and a higher resolution screen would be good, too - some apps just don't play well with low-res screens.

I've had my Jelly Star for just shy of two years now & I absolutely love it. It's amazing what they packed into such a small device.  I'm looking forward to the next one (and no, I don't consider the "Jelly Max" - with it's 5 inch screen and removed headphone jack - to be a proper successor). My wishlist includes just 5G support, better camera - including the software driving it, and a user-replaceable battery would be nice (or at least a larger capacity one since I'm probably still a heavier user than was intended).  Otherwise it was damn near perfect!

Some months after they released the Jelly Star, they also released a "Tank Mini" which had a 4.3" screen, a second programmable button, more RAM, and a battery nearly 3x the Jelly Star's capacity.  Had I known that was in the works, I'd probably have gotten that instead since I'm such a heavy user, but don't like big phones.  Still love the JS, tho - it's incredibly capable for something smaller than even a "communicator" from the original Star Trek show.

Some of the mentioned apps for KaiOS under the Nokia 6300 are no longer supported