Doom's unique dark atmosphere was maintained while a CRT filter and various other filters were applied.
This is a screenshot using Reshade from GZDoom
If you like it, take it.
(Written in Reshade version 6.1.1)
https://mega.nz/file/QEwgxK4Y#gClgsQom43jm_W2_3ptwnsGDYWFxDwunsBnSseqPxmQ
For Doom for Unity Engine, please visit the following link.
https://sfx.thelazy.net/games/preset/12504/