Reaching 83c while gaming on that CPU is definately not ideal.
Most studies show that CPU while running hard benchmarks like Aida, the avg max temp is around 85c for those tasks, which are much harder tasks than gaming. This was also using stock cooler and stock voltages etc.
Your idle temps are basically on the brink of being "okay" for idle temps.
You want more like 38-45c idle with 45 being the max end. However this would also depend on your room temp and environment
place you live etc.
Imo your 120mm AIO for that CPU is the issue. I would upgrade it as soon as possible. Also what kinda of thermal paste are you using? Are you sure you applied the cooler properly? Have you reapplied the cooler and applied your own thermal paste?
I know its a different CPU however my Ryzen 5 2600 never goes above 55c while gaming and those are sort of the temps you would want to be seeing on your cpu as well, however you would be looking for more like 65-70c because thats a powerful cpu.
Also, what voltage is your cpu running at? You can check with HWMonitor. Have you done any overclocking?
Its a known issue if the R9 3600 is running at 1.35v or above, there will be higher temps as the new gen cpus are more efficient and run more around 1.2v. SO I would check and make sure your not running at 1.35 or above.
Here is a video by JayzTwoCents on yt (highly respected tech channel) on some info about the 3600x and how to properly set it up for best performance while OC'ing and some other useful info. He even speaks on the voltage causing high temps issue.
View: https://www.youtube.com/watch?v=Ssuqhyqah2k