It’s weird, the game does update UserCfg.opt every time I change settings in game (timestamp changes) however it leaves the post process section as is.
Mine is located in C:\Users\MyName\AppData\Roaming\Microsoft Flight Simulator\UserCfg.opt
Others say it’s in C:\Users\Name\AppData\Local\Packages\Microsoft.Flightsimulator etc, however I don’t have that directory.
I haven’t tried any sharpening with NVidia, it’s simply set to Off there. I’m not looking for any artificial sharpening, but I do expect more from 4K downsampling to 1080p. I can’t believe that even without AA it looks so blurry without sharpen when downsampling from 4K. Maybe there is something wrong with their scaling algorithms.