stock cooler,
gpu: amd rx 5700 xt
mb: msi mpg x570 gaming wifi edge
case: evolveo ptero q1 (6 fans)
ram: hyperx dual channel 16gb 3200 mhz
Well, I can speak from experience, I also have a Ryzen 5 3600. Case is a Phanteks P400A, so mesh front. 3 intake, and 3 exhaust fans.
When I had the stock cooler, I ran prime95 and it would reach over 95C, was at 50C/60C idle.
After I got an Arctic Freezer eSports 34 Duo, now on Prime95 it stays at 66C and is very very cool idle. And I even overclocked it to a stable 4.4GHz.
The stock cooler is great to save a few bucks when first buying a computer, but please replace it, you will see much better values.