Ha, I considered buying this game for vorpX, might be cool.
The trick with UE4 games is to assign their less obvious Win64-Shipping.exe that they bury a few folders deep. It should be in the Binaries/Win64 folder, labeled something like LunchLady-Win64-Shipping.exe.
So create a copy of the Mordhau profile, add from file this Shipping.exe, and click apply. That should hook G3D, but might require additional shader treatment to clean up some shadow or texture glitches.
One more tip for UE4 games that don’t have a built in FOV slider: find Engine.ini in AppData (example: C:\Users\USER NAME\AppData\Local\LunchLady\Saved\Config\WindowsNoEditor….Engine.ini) … add these lines at the bottom and click save.
[/script/engine.localplayer]
AspectRatioAxisConstraint=AspectRatio_MaintainYFOV
This will generally give a significant fov increase from default. Good luck.