To be fair, it’s easier to emulate Switch stuff on an ARM64 device like the Steam Deck (or a Mac) because the games themselves are not that far removed from the platform. The Switch itself is just a modified Nvidia Shield tablet, and the OS was originally an Android fork (apparently, no production version was, but before it released that was the plan, since they were and did use an Android tablet). Translating to x86-64 is more work (but also not impossible because in 2016 when the Switch launched, it wasn’t a terribly complicated machine to start with).
To be fair, it’s easier to emulate Switch stuff on an ARM64 device like the Steam Deck (or a Mac) because the games themselves are not that far removed from the platform. The Switch itself is just a modified Nvidia Shield tablet, and the OS was originally an Android fork (apparently, no production version was, but before it released that was the plan, since they were and did use an Android tablet). Translating to x86-64 is more work (but also not impossible because in 2016 when the Switch launched, it wasn’t a terribly complicated machine to start with).