Hello
Basically, your selection is not bad, you seem to have chosen suitable components. However, you can still make some optimisations.
You still seem undecided about the RAM. I recommend you to take 2x8GB and not a 16GB bar, because 2 bars usually run faster. If you want to save some money, you can also use these:
G.Skill Ripjaws V (2x, 8GB, DDR4-3600, DIMM 288)
For the CPU, I would recommend you to go for the Ryzen 5 3600 instead, as the 3600X doesn't offer much better performance for the extra price:
AMD Ryzen 5 3600 (AM4, 3.60GHz, 6-Core)
As for the motherboard, you don't need an expensive X570 motherboard for any of your parts, unless you plan to install a high-end processor in the future. Instead, I recommend a cheaper (but still good) B450 motherboard that supports this processor:
MSI B450 TOMAHAWK MAX (AM4, AMD B450, ATX)
For the power supply, you don't necessarily need 850 watts of power, the 750 watt version of the same power supply is already far sufficient, even if you install more demanding components in the future:
Corsair RM750 *2019* (750W)
Memory, graphics card and case are all good components that you can keep.
The monitor is also top-notch and also in the correct resolution for the selected graphics card and also correspondingly expensive (you might find something cheaper with a little searching, if that's what you want).
What you don't need is the HDMI cable in your list. The monitor already comes with HDMI and Displayport cables.