Depends on what you’re comparing the 5600X against (it’s a CPU btw). If it’s against the 5800X or 5900X, then yes, I would suggest going with the 5600X for sure. The extra cores you get on the 5800X or 5900X will not be leveraged by MSFS at all. Those will only bring you extra performance in productivity workloads like rendering or video editing. The 5600X is the update to the 3600 CPU that’s currently listed in that pcpartpicker list posted above.
Don’t confuse the 5000 series CPU’s (Ryzen) with the 5000 series GPU’s (Radeon). AMD should really have made bigger differences between GPU and CPU naming schemes. It can get rather confusing if you only look at the numbers 
GPU wise; the 3000 series from NVidia are mostly beneficial at 4K resolutions. Just check availability though. They are pretty hard to get your hands on. Some older 2000 series cards are still pretty expensive. So it might be worth wile to wait for availability on the newer cards: Don’t spend almost as much or even more on a 2000 series GPU as you would spend on a 3000 series card if they were available.