If you own a physical cartridge and a homebrew-enabled Switch (via a modchip or early-unpatched model), you can legally dump your game into an NSP using tools like . This creates a backup ROM for portable use on an emulator (like Ryujinx or Yuzu) or on your modded Switch’s internal storage.
For those interested in learning more about Olympia Soiree ROM NSP and Switch game portability, here are some additional resources: olympia soiree rom nsp update switch game portable