the screens could've been edited in after taking the original snapshot, considering the inital Switch reveal also had the gameplay edited in post-production.

what I'm saying is that IF the screens were edited in post-production, they could've just used a random screenshot of the game when the console was in single-screen multiplayer, and there's no splitscreen when each player is using a seperate Switch unit.

also note that this game is still in development, so if there's always splitscreen multiplayer at this point in time, that can still change for the final product.