UltraWide (21:9) Specific Solution & Issues
This method assumes you have the latest patch (1.31). It involves setting a game var that did not exist in the earliest retail versions.
Resolution - Go to -> \d3xp
edit DoomConfig.cfg put in:
seta r_customHeight "1440"
seta r_customWidth "3440"
seta r_mode "-1"
seta r_aspectRatio "1"
Aspect Ratio 21:9 --> Extract and replace Files from Doom 3 ROE - Aspect Ratio - 21.7z
This fix is based on the 21:9 aspect ratio fix provided by WSGF for the Doom 3 base game only.
Doom 3 FOV Fixes - WSGF - PCGamingWiki PCGW Community