Topic on Talk:Red Dead Redemption 2
The statement is inexact. The exclusive fullscreen mode does work via Vulkan, but it is buggy. It gets automatically reset to borderless window at the refresh rate of your desktop (usually 60 Hz) every time you change a graphic option or you restart the game. You can easily reproduce this by selecting a 50 Hz refresh rate and the display will switch to exclusive fullscreen at 50 Hz, until you restart the game.