Reddit gives credit to this youtuber, that in the past has leaked some Nintendo things including Metroid Dread
https://twitter.com/NWeedle/status/1266833951898906632?s=20
Translation
"Leak Express: New Metroid 2D for Switch could be "Metroid Dread"
It would be the sequel to Fusion.
This game...
With how weird the new Mario game is, I swore that it was going to end with a Switch 2 announcement. Even in the direct they never mention that the game will be on Switch (though the standalone trailer does).