I feel like once you set third-party apps like Uber, bike rental or banking apps as requirements, the only possible solution is sadly a mostly standard cut-down Android phone. The third parties won't support any bespoke OS, so you're stuck with iOS or Android, and moreover they won't support exotic configurations like a tiny display.

Thankfully on Android it's easy enough to remove/disable any distractions, and there are phones like the ones from Unihertz that are just different enough to be worth trying.