Have you tried this. It really helped me out.
Stutter Fix - Sim Update 3 - Community / General Discussion - Microsoft Flight Simulator Forums
My Rig
Processor - Intel® Core™ i7-9700K CPU @ 3.60GHz 3.60 GHz
Installed RAM 32.0 GB
System type 64-bit operating system, x64-based processor WIN 10
GeForce RTX 2010 Super
Driver Version 461.72
Intel Core i7-9700k CPU@3.60GHz
31.91 GB Ram
Monitor HP 2560x1440, 59Hz