Graphics Settings

• The first screens deal with the usual monitor and resolution options. If you just installed the game and are unable to change the resolution to 4K because it is grayed out, switch fullscreen mode away from the default of "windowed" to "fullscreen" to enable the 4K option.
• The game only supports 16:9, which means 16:10 (2560x1600) comes with black bars. The same will happen when a 21:9 monitor is used.

• The remaining options are few and can't match what we are used to from PC gaming.
• The options for AA, Post-processing, and shadows are nondescript, and just represented as numbers. A more detailed explanation would have been nice; it's not like there isn't any screen space available for that.
• The FPS cap can be toggled between 30 and 60 frames per second. Again, not good enough! Especially considering that a V-Sync disabled option exists.
• Thanks to the use of Unreal Engine 4, you can unlock the FPS by manually editing GameUserSettings.ini located in My Documents\My Games\DRAGON QUEST XI\Saved\Config\WindowsNoEditor. Here, you change the value of FrameRateLimit=60.000000 (use a high number like 1000, not 0 as that doesn't work).
  I've played most of the game with FPS set to 1000 and didn't encounter any weird issues with gameplay, animations, or physics.
• You may also use super-sampling (rendering at higher resolution) if you have FPS headroom by playing with the "ScreenPercentage" value in the same config file.
• Engine.ini in the same folder can be edited manually, too, to increase the draw distance, LOD distance, and shadow quality as outlined in this post.
• More info on possible INI Tweaks can be found in the Unreal Engine Developer Documentation.