Hi, first of all, I would move X-plane 11 folder directly to the root of your D:\ drive.
And then, mainly, I would try and delete the entire ...\X-plane 11\Output\Preferences folder. You will have to set everything again, but it will be almost like coming back to a clean install.
About your X-plane graphic settings, very important, shadows off, Vsync disabled, objects not too high, effects not too high, Something like that should be satisfying (30-40 fps depending on where you are) :