The Switch is ARM (nvidia tegra x1) while the Deck is x86 (amd zen2?). There’s translation involved. Not saying that will guarantee a slowdown, but as @FireWire400 said, if the emulator is shit power won’t help much. My oc’ed ryzen 5600x could barely run switch BOTW at 15fps when it first released (though that was arguably still better than the experience I had on my Wii U… shudder)