The developers of the game Atomic Heart, answering the questions of the players, talked about the resolution and frame rate of the game. According to the developer comment, the game will run at 4K resolution and deliver stable 60 fps in closed locations and have dynamic resolution and also 60 fps in the open world.
Obviously, only the Xbox Series X is meant, the resolution will most likely be lower on the Xbox Series S. It is worth noting that this is a loud statement, since quite a few modern games are capable of showing such stable performance.