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Sega, Xbox, Steam - and functionally speaking, even Sony all default to a face button scheme with the action/enter/accept button on the bottom, and cancel/back on the right. Nintendo's control scheme is really the primary thing that throws a wrench in retro handheld setups. It's also just a bad layout. X on top? What is that nonsense?
Just like Sony uses? Circle being enter/accept and X being cancel/back was the original intention, but that got mixed up in the US almost immediately and it wasn't long before X became equivalent to A in most games in all regions even on the original ps1. For the vast majority of games, the Sony layout is effectively the same as the Xbox layout, just with idiosyncratic glyphs.