If the CPU Processor temperature is not reaching 90c then the problem is not overheating but either incompatible hardware like RAM MEMORY, BIOS issues, Power issues.
Try doing a CLEAR CMOS to reset BIOS back to factory defaults and see if the problem continues. Could be a BIOS settings you have configured causing problems.
Is your PSU strong enough for your GPU card that you have installed?
What errors are you getting when your PC crashes?
Any Motherboard Trouble LEDs or Digital Codes showing when it crashes?
You can try running OCCT CPU,GPU, & PSU Tests if possible to see if it is a overheating or power issue or hardware issue.
Run SFC /scannow to check your Windows Installation.
Also run DSKCHK C: to see if there are any errors in your Windows Drive. IF a SSD then use your SSD diagnostic software to check it.
Check to make sure your RAM is listed either on ASUS 5000 Series QVL LIST for RAM MEMORY or the RAM Manufacturer's support site to rule out incompatible RAM.
Also run MEMTEST86 or Windows Memory Diagnostic to physically check your RAM for being defective.
Install Ryzen Master and run it. See what temperatures are showing. Also check the top icons on Ryzen Master. They should all be Green or Yellow. If Red than the CPU is being throttled either by the CPU itself of the Mobo.
If unable to install Ryzen Master then install something like CPUID or Temp Core or whatever software you have installed that shows real time CPU Temps and run it as soon as you enter Windows and see if the CPU or something else is overheating.
Update your Motherboard's BIOS and AMD CHIPSET Drivers to the latest version.
NOTE: You Processor's Maximum Operating Temperature is 90c and it is rated at a TDP of 65 Watts. So you will need a CPU Cooler rated at a TDP Rated 150 watts or higher to prevent your processor to reach 90c or above.
