Ryzen 3600 max temp is 95c, but even 77c is too hot for me (but that's just me).
And the stock cooler is best for stock speeds. I have the same experience with my Ryzen 2700. I got 3.3GHz at 77c. Changed the cooler and temps dropped to 53c. Huge difference.

If you want to overclock I would suggest you change your cooler to something beefier. Which model, depends on whether you want air cooling or liquid cooling, and how far you want to overclock.