Look for a setting called Platform Thermal Limit and set that to something like 80C or so. In an MSI motherboard it will be in the Overclocking section, in Advanced CPU settings.

You may have to Enable PBO, set it to Manual but don't change any other settings and it won't do anything. When it gets to the new temperature limit it will just pull back on CPU frequency and voltage to keep the CPU under that limit. But short of that temperature the CPU still gives you full performance. Hey I'm experiencing the same issue with a 3600 and I think a combo of these solutions might work but I don't know enough. I'm idling at 65C, when I load NFS: Heat I hit the thermal limit and it shut off last night which is what got me investigating. I'm running default everything, I've changed Windows Power Saver to 10% instead of 99% min, I cleaned and reapplied thermal paste, I'm using Ryzen Master for the temps, and nothing has gotten it any lower. I found this thread and I tried undervolting by 0.05, and it went down about 5 deg. That being said, I don't know which option is better.

B450 tomahawk fan control