Don't confuse the game disc with the subscription. Just Dance 2025 comes with about 40 new songs. To access the 200+ older hits, you need ($3.99/month). A pirated ROM cannot access this server.
Unlike older consoles (GameBoy, NES, PS1), the Nintendo Switch has robust security. Here is what you need to know: just dance 2025 rom switch
Technically, if you have an unpatched first-generation Switch (2017-2018) or a modchip installed, you can run backup copies. However, for Just Dance 2025 specifically: Don't confuse the game disc with the subscription