RSDuck has released a GBA Emulator for the Nintendo Switch:

A quick port of VBA-next(VBA-M https://github.com/libretro/vba-next). I developed it on 4.1 so, it definitely works on this version. It's partly based of 3DSGBA https://github.com/shinyquagsire23/3DSGBA.

I tested it with only a few games, but as far as I can tell they run great, except the menu of Fire Embled The Sacred Stones, were the music in the start menu has small hiccups.

download https://github.com/RSDuck/vba-next-switch

via https://www.nintendomax.com/viewtopic.php?f=168&t=16585