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

https://wiki-triod.win/index.php/How_Do_Browser_Controls_Reduce_Usable_Screen_Space_on_Mobile%3F

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-friendly controls that feel natural on small screens