Baseline (Widescreen) Solution & Issues
The Game only Supports Widescreen till 1280x720 - You need to HEX edit some Files for more resolutions / FOV / Sonar and FONT Size.
Resolution: Go to --> C:\Users\...\Documents\Rogue Trooper and edit save0.rtp
Go to Offset 17C and change 00 05 00 00 D0 02 --> 00 0A 00 00 A0 05 (2560x1440). See all resolutions here - see also Addtional Pics
FOV: Go to --> Rogue Trooper and edit this File RogueTrooper.exe
Go to Offset 6F570 and change 00 00 80 3F --> 00 00 A0 3F
I created some Files for Resolution and Aspect Ratios - Rogue Trooper - Resolutions.7z & Rogue Trooper - Widescreen.7z. Fix available from the PC Gaming Wiki Community Files (search there).
Ultra/Super-Wide (21:9/32:9) Specific Solution & Issues
Same Solution as in Widescreen.
Optional you can make the Sonar transparent: Go to --> Rogue Trooper and edit this File RogueTrooper.exe
Go to Offset 194B40 and 194B50 and change 00 00 80 3F --> 00 00 00 2F
Eyefinity / Surround Specific Solution & Issues
Same Solution as in Widescreen. See Additional Pics and File Attachments.
Issues: The high FOV creates a side effects off popping Textures & the HUD is huge.
4k UHD Specific Solution & Issues
Same Solution as in Widescreen.