Make a copy of the UserCfg.opt file for backup, you can copy it back to revert the graphics settings.
Microsoft Store Version
C:\Users\your_login_name\AppData\Local\Packages\Microsoft.FlightSimulator_#############\LocalCache\UserCfg.opt
Steam Version
C:\Users\your_login_name\AppData\Roaming\Microsoft Flight Simulator\UserCfg.opt
NB: if you’re using GE Force Experience automatic settings, this most likely be the cause for the UserCfg.opt setting to reverting to 1 too. You’d have to disable GE Force from automatically updating the settings then. Please let me know this so that I can update the post accordingly.
NB: Please make sure to change the correct Sharpen entry, there are 2 of them: One in the {Graphics section, the other in the {GraphicsVR section (which is the entire set of settings when in VR mode).
PS: I don’t use GE Force Experience. Thank you all for pointing the typo in my post!