You have to understand that Flightsims are different from “other titles”. You will not reach 60FPS constantly with actual hardware right now. Maybe somewhen in the future, but not yet. Stop chasing the frames, its a waste of time. 
Smoothness is your goal. Set vsync 30FPS and enjoy a smooth sim. Happy flying!
EDIT: also stop throwing money at it, i have an i7-9700K and a ASUS STRIX 2080Ti OC. I can not get 60FPS. so, dont do it.