https://steamcommunity.com/sharedfiles/filedetails/?id=3083822863 <-- Steam guide with further details and explanation.
Ultrawide and triplewide setups will suffer from stretching at the edges of the full display. With a few additions to the Engine.ini config, we can leverage Unreal Engine's built-in Panini Projection algorithm and eliminate all of that stretching. UE's Panini projection implementation is based off a well known thesis of human/artistic perception versus rectilinear projection that is commonly used to display 3D worlds in video games.
More accurately predict distances, get a better and more accurate sense of speed, have clearer visuals through corners and bends, immerse yourself more, and ultimately, hopefully have more fun and set better times.
This in-engine feature uses a post-process to manipulate and upscale the rendered scene based on 3 variables and then displays the altered render.
Simply download and extract to %APPDATA%\Local or dig the file out of the folder structure and place into the WindowsNoEditor Folder. You can also add the lines to your Engine.ini config:
[SystemSettings]
r.Upscale.Panini.D=1
r.Upscale.Panini.S=0
r.Upscale.Panini.ScreenFit=1
r.Upscale.Quality=4
r.ScreenPercentage=100
Default Rectilinear Projection
New Panini Projection
Default Rectilinear Projection
New Panini Projection
https://www.racedepartment.com/threads/fix-triplewide-ultrawide-stretching-w-panini-projection.265529/post-3724993
I added the above to mine recently to help with any blurriness or LOD issues if you are using drivers head cam. Depending on your specs, you can push some of those up higher and get an even better picture.