Zelda is confirmed to be 4k :/ both from those who played it and Nintendo.
https://www.videogameschronicle.com/features/we-played-nintendo-switch-2/
"At 4K 60fps, Tears of the Kingdom is undeniably a better experience here: this is a monster adventure game that still chugs on the original Switch, and revisiting it in silky-smooth form on Switch 2 feels like a compelling offer, especially because it’s being bundled with the Switch Online Expansion Pack."
Edit: Apparently those numbers in the tweet were obtained by DF from testing youtube videos lol, DF have not had a s good time recently as they said it would not be possible for Switch 2 to have a 1080p screen.







