If those temps are accurate then you have a real problem. Either the CPU cooler is not seated correctly, maybe one of the retainers is not properly latched down, or something else is going on with the mount or paste job. Or the configuration has been altered.
First thing you should do is make sure you have the MOST recent motherboard BIOS version installed.
Second thing you should do is go download this chipset driver and install it.
https://www.amd.com/en/support/chipsets/amd-socket-am4/b450
Then go into the Windows power options and make sure the power plan is set to AMD/Ryzen balanced. Then go into the advanced power options for that power plan and set the minimum processor power state to 8% (If it's already set to 5% then leave it).
Save settings and exit the power settings applet.
Restart, go into the BIOS and set all of the following.
Cool N Quiet - Enabled
Core CPPC - Enabled
CPPC preferred cores - Enabled
Advanced/Global C-states - Enabled
Precision boost overdrive - Disabled (Until you have a much better cooler, this is pretty much a must-do)
Precision boost/XFR2 - Enabled
But before doing any of that, double check the cooler mounting and outlining what your case cooling configuration looks like would be helpful as well.
The MORE important consideration is what temps do under a full load. It wouldn't really matter if you were idling at 65°C but maximum full load temp was 80°C or less. By full load temp, we are talking about running a full 100% TDP steady state stress test like Prime95 Small FFT with AVX and AVX2 disabled. Run that for 15 minutes. If at any point you exceed 80°C then go up to the File menu and select Stop, then exit Prime95 and plan to figure out why you have a cooling problem. Do not simply click the X in the top right corner as you would for most programs as this will only minimize the utility and will not stop the workers from continuing to run. You MUST click File > and then either Stop or Exit.