Kingdom Hearts 3 will offer two different gameplay modes that prioritize performance or visuals. You are free to pick between any of them depending on your tolerance to the frame rate.
As Kingdom Hearts 3 is out on January 25th in Japan, it is now playable through the digital pre-order on PlayStation Store. For the rest of the world, they will have to wait until January 29th. Square Enix never confirmed any kind of performance mode on the PS4 Pro or Xbox One X, but that is not the case with the final game where the choice of two different modes is present in the game.
The two options that are available to pick here–supposedly from the PS4 Pro and Xbox One X version–are “Standard mode” and “Stable mode.” Here is what the description translates to from Japanese. It is likely different for the localized English release.
Looking at it, there are two different gameplay modes here, each focusing on a specific area. One will provide better visuals by running at presumably a higher resolution. The other will offer a better frame rate but at the cost of visuals.
Kingdom Hearts 3 did get a prologue with the release of Kingdom Hearts 2.8 but that was running at an unlocked frame rate. It is nice to have the choice to pick between these two different modes and it will greatly help those who have the mid-generation console upgrades with a 4K TV.