Look at this comparison here. I have both of the AMD processors there. Both of them stutter a little bit. The machine where I have the Ryzen 9 3900X runs with High graphics on a Radeon RX 5700 XT. The machine with the Ryzen 9 5900 has a Radeon RX 6800 XT and runs Ultra graphics.
I’d say that Flight Simulator can benefit from a faster CPU. It is complicated because even while it uses all CPU cores available, it still seems to rely on single-core performance for some tasks that cannot benefit from concurrency.
Your CPU has a low CPU mark compared with mine, but both its single-core performance and its core count seem to be high enough so that you can at least get up to 55 FPS with minimal stuttering outside the largest cities (New York is pretty heavy and your performance can drop as low as 30 FPS with annoying stuttering depending on your graphics settings).
I found that there is no way to avoid a little stuttering, even with a powerful system running medium/low settings. Flight Simulator probably needs a bit more optimisation on the CPU side of things. Or maybe Asobo ran out performance tricks, which is why they can make this look so good and run almost smoothly.
Some monitors have a way to show the refresh rate for diagnostic purposes. When Free/GSync is enabled the refresh rate will be all over the place. If it is not working the refresh rate will look stable at 60 Hz, usually. Try to find that in your monitor and activate it. That should at least give you assurance as to whether GSync is actually being used.