the PS4 rarely drops bellow 1080P and not by much, check the digital foundry analysis
60FPS vs 30FPS is huge, rare resolution drop to is not
regarding the PS4 Doom:
"it boasts a full 1080p output for the vast majority of the duration"
"On PlayStation 4, the majority of battles play out with only the smallest of drops."
Doom is 1080P60, Mankind Divided is going to be 1080P30 on the very same hardware.
Doom consoles was far more impressive than the PC port which runs poorly on lower end hardware (with specs similar to consoles)
unlike other multiplatform games
and Vulkan patch is very broken if you don't have the hardware they optimized for