Obviously higher speed ram helps alot. Get what you can afford 2x8 3600 are on sale for 75$ often. Save the 8gb for backup or sell it.Going for higher speed RAM for gaming looks pointless:
RAM für AMD Ryzen von DDR4-2666 – -3600 im Test (Seite 2)
RAM für AMD Ryzen im Test: Spiele-Benchmarks mit DDR4-2666 bis -3600 / Testsystem und Benchmarks / Spiele-Tests in Full-HDwww.computerbase.de
Dual channel appears to be worthwhile though.
Heads up since you have a ryzen 2600 you may have trouble running them at that speed, depending on how strong the IMC in your chip is, and what motherboard you have as well.
If you have an A320 board, you may not even be able to change the frequency on the memory to get those higher speeds, though I am not sure.