NV Surround has always stretched the display - Its just the way that it works. The level of distrotion depends on how wide the desktop is. But in my case where I’m trying to expand it to 4 x 4k displays the distortion is quite noticeable.
The solution in Flight Sims has always been proper multi monitor support which was very good in P3D with ViewGroups and works in MSFS with the experimental multi views.