what you often see is just Nvidia surround … (or AMDs version) … that’s just combining monitors to one logical screen. That is nothing Asobo has to support, despite the higher resolution that comes with it, as its already implemented on a driver level.
Really supporting multiple monitors needs the rendering of multiple viewports (in different perspectives). That way you can place those Monitors as you like (i.e. one for your front view and two tilted 90 degrees left and right of you as “side-windows”)
NVIDIA-“Surround” is actually a really bad name for what they do - they actually expect you to set up all the Screens in a single plane of view (not angled to the viewpoint) what sounds to me like exactly the opposite of “surround”. If you position them even slightly angled the edges look really distorted to the observer.
The thing that is disappointing for most cockpit-builders is, that Asobo clearly stated msfs2020 would be released with (amongst other cockpit builder features) multi-monitor support … and all we got as their “support” is already implemented in the drivers of the GPU (what is actually just support for big but still flat resolutions).
If you want more information, there are some videos about “simultaneous multi projection” from way back in 2016 on YouTube where NVIDIA implemented support for just that … unfortunately besides VR (basically the same technique with two perspectives), developers didn’t really make much use of that since then.