I suggest having a good hard look at your settings. With your system you should NOT be having the issues you are describing. I would start by ensuring everything is running at stock levels. No overclocking or V adjustments. NVidia controls default and Experience disabled.
Get a base line from there and then start trying some of the adjustments, here…
I have a pretty middle of the road system and am only running 1080p, BUT I have most MSFS settings on Ultra or High and generally humming along at 45-50 fps with no stutters. Just for a test I tried 1440 on a small monitor and still managed 30-35 smooth.
There are obviously some issues that Asobo could improve on with the optimization but in general the sim runs pretty well since the last update (aircraft issues aside).
- B360 MB
- Corsair 32GB 2666
- i5-8400
- RTX 2060
- 1000w Corsair PSU
FYI, do not even dream of 60fps locked at 4K Ultra. It ain’t gonna happen without alien technology.