what disk did you install it on? Right click the game on the steam library sidebar, press installed files and browse. then find the doomconfig file

Doom 3 is not in my program x86 idk why

3840x2160 is working for me setting the highlighted values in OP's picture.

r_mode -1 is essential for this to work, since that tells the game you're loading custom values. I also noticed that if I change something in the setting menu in the running game, that value gets disabled, so I had to go back into the file a second time and set r_mode -1 again after I upped the game to Ultra.

You can verify that it's running at a higher resolution by checking the Steam overlay, or enabling the new "Overlay Performance Monitor" which will render crisply if you're at an HD resolution. The Steam overlay will look very blurry at lower resolutions.

Thank you very much!
this is simply fix, Why ID software won't make it to default?
this Time is 2025 already! why still not widescreen?

I have a couple configs set for 1080p or 4k that also help if you are having issues with texture resolution. even on ultra.

This sets the texture resolution to full.

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3517096527

I tried these changes and now the scree goes black and message telling me "Entry signal out of limits" appears in center. I tried changing to other resolution but it reverts to the original... I'll just play BFG instead...

Thanks for the guide!

You should defiantly try REDUX 25th Anniversary mod! Once you tried it- you cannot live without! ;)

set r_useTrilinearFiltering "1"
set r_maxAnisotropicFiltering "8"
set r_useSRGB "0"
set r_windowHeight "1080"
set r_windowWidth "1920"
set r_windowY "0"
set r_windowX "0"
set r_customHeight "1080"
set r_customWidth "1920"
set r_fullscreen "-1"
set r_MegansFinalForm "0"
set r_DisplayDeviceID "0"
set r_vidMode "0"
set r_multiSamples "8

it's work on my Samsung odyssey G4 27" FHD 240hz, but when i close the game and restart the screen resolution back like before... can i do something for let 1920x1080 permanently???

whenever my game is at full screen it blinks constantly which results to it being unplayable unless i exit full screen and put it in bordered mode. any suggestion to fix?