Personally I would go with the 1600x on a good B450 motherboard with 16 GB's of 3200 MHz RAM.
That you can upgrade to a Ryzen 2000 or 3000 series CPU in a year or two.
The 1600x is only slightly slower than my Ryzen 5 2600.
I run my 2600 at 4 GHz and get between 85 and 120+ fps on current games.
So with a 1600x and a GPU similar to my GTX 1660 Ti Armor OC you should get very similar performance.