Hi,
Because there is such disparity between all of our machines and the components therein, sadly, I have nothing to offer by way of a panacea! Indeed, to do so would, in my opinion be straying into the territory of the salesmen of snake oil! And we have enough of those already!
But in rather more general terms:
Start with your GPU software. If it allows, limit your max frames to a sensible 60 [if nothing else this will stop your GPU eating itself when in the sim’s menus].
Set your monitor tech to: G- Sync compatible [if you have a G-Sync monitor].
Make sure your power management is set to Maximum performance.
Set your Pref refresh rate to Max available, and vertical sync to Application controlled.
Further, if you are unsure as to the pros and cons of these and all the other GPU settings, do a bit of research. There is a lot of GOOD info to be had on these forums and via our friend, Google!
Turning to MSFS 2020’s own settings. Beyond suggesting using the built in general presets as a starting datum and experimenting by changing ONE ITEM AT A TIME and testing for efficacy, I am [for the reasons already discussed] loathe to be any more specific.
For me [with my i9-9900K and 2080] I use the Ultra setting, no Vertical Sync, Anti Aliasing set to TAA and Anisotropic Filtering at 16X.
Again, I cannot stress enough the importance of a little research here!
One final point: I am now enjoying stutter free flying with an in air FPS of 45 [+/-]
and an on the ground [at med to large airports] FPS of 39 [+/-].
Good luck [and let me know how you get on].