Your storage

I can’t speak to switch 2 performance, but the game was just mediocre to me, but performance was fine on switch 1.

Even if it did have firmware, the card is burned months ahead of shipping, and launch day firmware was finalized only days or weeks before launch. A game that comes out 6 months later might have launch day firmware, but that’s likely outdated by the time of release.

That’s not a complete overhaul, I’m talking about something like Fortnite from 8 years ago to now. That’s no shared code left. That’s not a game that came on cartridge, obviously, but Animal Crossing only got a few tweaks and some additional content. It isn’t an example of what a key card represents.

The system update would come from the internet in this case as well.

The key card acts like any physical that has a complete overhaul post launch. The physical goes in, the game plays from internal storage. It contains no game data, and you have to download the full game from the server.