Typically speed trumps timings. However, you will get diminished returns as you increase speed and therefore will want to tighten up your timings at some point. I was previously running Gskill 4600mhz 16GB (2x8gb). I decided to increase my memory to 32gb, but at the time, the fastest ram I could find was Gskill 4000mhz (2X16gb). MY motherboard is a EVGA Z390 Dark it only has two dimm slots, and was specifically built that way for overclocking. I ran benchmarks to see if I would get better performance in DCS VR with the increase in ram 16gb vs 32gb. Sadly, I did not get any performance increase or decrease in DCS VR in any configuration I tested. The 16gb at 4600mhz with the same timings as the 4000mhz 32gb, no change. Reducing the 4600mhz 16gb down to 4000mhz vs 32gb same timings, no change.
Even though my system was using almost all 16gb of ram with the 16gb set and up to 25gb with the 32gb set, in DCS VR, there was zero performance change from one configuration to the next. I gave my 4600mhz ram to my Son to add to his system, which put him from 16gb to 32gb (4x8gb) on a Z170 with 7700k and a watercooled 2080ti. He saw no performance change in DCS VR.