Ubisoft has confirmed that Assassin’s Creed Valhalla will indeed run “at 60 FPS in full 4K resolution” on the Xbox Series X.
Additionally, the game’s release date has been brought up one week and will now release on November 10 across all platforms. The accompanying press release (via Gamasutra) stated the following regarding the Xbox Series X | S version of the game,
“With the Xbox Series X | S, Assassin’s Creed Valhalla will take full advantage of the enhanced graphics, giving players the opportunity to experience the open world of Norway and England down to the very last detail. On Xbox Series X, Assassin’s Creed Valhalla will run at 60 FPS in full 4K resolution.”
Note that the press release does not mention “dynamic” 4K, nor “up to 60fps,” indicating that the game will indeed run at a locked 60fps and native locked 4K. We're also not sure what resolution the game will run at on Xbox Series S.
Assassin’s Creed Valhalla is also set to offer higher resolution textures and improved shadow quality on both Xboxes (and presumably the PS5, but this has not been confirmed). Clutter density will also be improved. This is on the back of Microsoft confirming the $299 price for Xbox Series S, $499 for Xbox Series X, and November 10 release date for both consoles.