Not this this is documented anywhere, but you need to find out what chip is being used for a temperature sensor and where it is located. That information is not generally available anywhere - the BIOS manufacturer “might” be able to help as they usually have access to it.
If the hardware is new enough, and has an ACPI bios, you may want to look at the ACPI source which Intel makes available. The intent is to provide an OS agnostic approach to getting that kind of info. The problems include that the BIOS manufacturers don’t always follow the spec correctly and often the ACPI code is incorrect.
The source for the ACPI support may compile in 4.25. I have it somewhat working in 6.x, but it really depends on whether the BIOS manufacturer supported the features you wanted.