A screenshot was tweeted by the official Animal Crossing Twitter page, in which it appears the image is shown in 4K. The thing is, the Switch cannot output 4K screenshots, and normally outputs its screenshots in 720p. The screenshot can be found below:
Now usually, I would dismiss this as just another reach, as it is known that developers can take screenshots in developer environments, on much stronger hardware. Although, if you look back through previous screenshots shared by the Twitter page, you'll find that they actually use the resolution of the Nintendo Switch. As can be seen in the images below:
Images from Tweet:
This doesn't confirm anything, although it certainly could be a little clue as to what is next for the Nintendo Switch. Although I implore you to not read into this too much, as we stated before, it is most likely just that the developer took the image from a developer environment.
This was on Reddit Rumours, by user C-Ron. You can find his post on Reddit here, be sure to upvote it, if you believe this to be true!