mobile testing that works the same on iOS and Android without separate configs, does this exist
Every React Native testing setup eventually breaks at the platform boundary. Detox has iOS bias, XCUITest is iOS only, Maestro has platform specific quirks, and you end up running two different strategies for a codebase that's supposed to be write once run everywhere.
The whole point of React Native is cross platform parity. The testing layer almost always violates it.