Im aware you cannot make it run with every "game" there is out there but the flightsim world is not really big, there is 2 simulators that is xp11 and prepar3d. Its a lot of people using this simulator and we cannot use reshade in a normal manner. The only working version was 3.1.1 and 3.1.2, all after that brought major errors into the sim.
As time passes without an updated reshade we get into trouble. Now more releases come out where even the old 3.1 crashes things so reshade is soon fully unusable im afraid. This would be a major loss. If you are interested to fix this i would make a call in various forums and communities to donate to you. We need this!
The latest of these releases was a plane the whole community was eagerly awaiting. Just to see that the best function of it is unusable with reshade. And not even on a very deep level. There i s a popup that has one registering online and this popup crashes the sim then, or better said due to reshade the directX framework seems to crash after opening this popup.
Same as the overall problem with reshade after 3.1.2. Its only an UI thing. Probably shaerwise things would be the same but we cannot use the reshade UI in those versions. Only the good old 3.1.1 does the trick.
You can find many many posts here about this by entering prepar3d into search.