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

https://trentonsexcellentthoughtss.evergrovio.com/posts/how-to-design-a-spin-button-for-one-handed-play

Designing a full-sized game for a five-inch screen is all about smart priorities, not just shrinking everything down. You focus on touch-first controls that feel natural in your hands. You choose portrait or landscape based on how players hold the device