Neo's are good for Ryzen, and 5 series cpus support upto 4000 officially, but rarely get there, usually 3800 is tops. 3600 is a no brainer for that cpu. DDR4 default speed is 2133MHz. Motherboard chipsets and cpu IMC can boost that, so you'll see 2133-3200 as is, but 3433MHz and up may have an (OC) next to it, meaning it's beyond official support of the motherboard and cpu and requires docp/xmp or manual settings. The ram is guaranteed to reach rated speeds, but there's no guarantee the motherboard/cpu will allow rated speeds, it's (OC) after all.
@ Op. You have to be careful about settings, and understanding them fully. I'm betting you are doing 2 things. First, in bios you are sticking the cpu in Asus Performance mode, and in windows your power plan is also in performance mode. That's going to jack up the Hz of the cpu and not allow it to settle into idle frequencies. Standard/balanced is best. Which happens when you return the bios to factory default settings.
Secondly, you most likely are making assumptions. Most reported numbers are from fastest/hottest/highest values. Windows might report you are at 4.8GHz, but generally that's only the fastest core, the rest could easily be at 3.8GHz. That applies to temps as well, you might be at 60°C, but that's only 1 core, the hottest at the time of reading, but the others could be at 36°C easily.