With timings of 16-18-18, you do not have Samsung b-die memory which is the variety that has has all the love in bios development to date. If you do return and swap it out. Look for ideally the C14 14-14-14-34 timed memory sku or the 16-16-16 memory which also has had sucess i believe.
In the mean time, Have you tried booting with a single stick of ram and getting that to 3200mhz?
have you tried increasing SOC voltage to 1.2v? If that doesn’t help increase to 1.25v and retry. In extreme OC guides that say 1.35 is the absolute max but I would try to stay below 1.3 as extra voltage will also increase temps.
If nothing else it will allow you, by a process of elimination, to determine if one of the sticks is faulty or if it is motherboard settings giving you a challenge.