Apple’s rumoured foldable iPhone (possibly iPhone Flip) might launch in 2026, but display crease, and design are roadblocks.
Look at Kyocera Digno 903KC, Sharp Aquos K3 or Freetel Mode 1 Retro II. Their idea is retro design with somewhat modern OS. It’s still Android but very old one. None the less you can run WhatsApp, Signal and the like.
I’ll look into those. That Sharp looks ancient though? I’m seeing videos on it from 6 years ago, assuming it’s the correct one.
It’s likely my memory is out of date, but at least you have a starting point for search. They make those kinds of phones. I know Samsung has Galaxy Folder. Not to be mistaken with Fold. Only thing am aware of that was released recently is Cat S22 Flip, in 2021.