Is it possible that the heatsink is installed incorrectly?
Wipe off the paste with Isopropyl and Coffee Filters (Anything Else Lint Free Would Be Nice But If You Don't Then A Sheet of Paper Towels would work) and replace it with something like Arctic Silver 5, MX2, MX4, IC Diamond, Kyronaut (bit overkill) (Just Any Thermal Paste That is Reputable and not like big cheap Chinese paste since due to personal experience it doesn't preform that well and can lead to undesirable temperatures)
Ambient Temps? I've seen systems with Ryzen 5 1600 with the stock cooler hit 50c-60c just sitting there in the BIOS with about 20c-25c ambient.
Not enough airflow can be a possibility but I'm not sure about your situation.
I recommend buying something like single or duel tower cooler or even better a duel radiator all in one liquid cooler. to tame that beat if you have any money laying around.
What I'm saying is that it seems to be normal and many factors can play into the temps your CPU will run at and it's best to get a aftermarket cooler if you don't like the temps your seeing on your chip.
i found out that my ryzen 5 1600 is like ryzen 7 1700x (check cpu-z screen)
so, i have cooler from 65w 1600 box and my real CPU work like 95w
so, I think this is the reason of temperature
btw with full load in windows i have 65 C maximum
CPU: Ryzen 1600 with included Wraith cpu fan
MB: Asrock B350 Gaming Fatality K4
CPU temp in BIOS All fans in SILENT mode: 58.5c
CPU temp in BIOS All fans in STD mode: 52.5c
The BIOS must not activate any power saving modes so thats why its not lower. In HWInfo my CPU temp is ~38c using AMD power plan.