Designing a full-sized game for a five-inch screen is all about prioritizing...

https://stateofseo.com/how-do-you-test-mobile-game-ui-for-thumb-reach/

Designing a full-sized game for a five-inch screen is all about prioritizing what matters most. Instead of just shrinking everything, you focus on touch-first controls that feel natural in hands. Portrait mode often works better than landscape here