This tech tuber has a theory as to why Ryzen 9000 series X3D CPUs are dying mainly on ASRock motherboards. Apparently, on ASRock motherboards, when the "SOC/Uncore OC Mode" setting in the BIOS is set to Auto (as it is by default), its effective setting is Disabled, which allows the SOC voltage to fluctuate and potentially go higher than it should. When it's set to Enabled (or, on other vendors' boards, when Auto defaults to Enabled), the voltage stays constant, which is preferable. I don't really understand why the SOC voltage (and not the CPU voltage) would fry the CPU, but it does make sense that a different default for a BIOS setting could be why it's affecting mainly ASRock boards, and the few cases of other vendors' boards frying CPUs could be simply due to people manually changing the setting to Disabled for whatever reason. Anyways, if you happen to have an ASRock motherboard and a Ryzen 9000 series X3D CPU, or know someone who does, you might care to set "SOC/Uncore OC Mode" in the BIOS to Enabled just to be safe, in case this guy's theory is correct.