Unfortunately, Open Hardware Monitor hasn't been updated to work with the new Ryzen 5000 chips yet. Hopefully that will happen soon, I was having this same problem a few days ago with a 5800x.

The ASUS AI Suite gave CPU temperature readings, but it's fairly heavy and would likely conflict with some of those other tools.

Ive managed to fix it.

I was not implementing Ivisitor and LibreHardwareMonitor seems to be the updated version of the dll (i had to got it via nuget as it has to update some independeces)

Here i found the example code with the Ivisitor implemented: https://github.com/LibreHardwareMonitor/LibreHardwareMonitor

All the information you need is found in the map, in C++ this is a map of tuples, each holding three data points:

0. Sensor Name
1. Sensor Type
2. Sensor ID (this is what you want)

Each piece of hardware has various sensors of various types, each with their respective values. In your case, you want to find a sensor of type Temperature.

You find all this information with the provided LHWM::GetHardwareSensorMap().

For example. I found my CPU AMD Ryzen 7 PRO 4750U with Radeon Graphics, where within the many tuples I found a single sensor of type Temperature with the ID /amdcpu/0/temperature/2. So, I plugged that in as follows.

std::string sensorId = "/amdcpu/0/temperature/2";
float temp = LHWM::GetSensorValue(sensorId);
std::cout << "Temperature: " << temp << std::endl;

Which gave me the value 57.625 in degrees Celsius.

Note: The program must be running with elevated privileges, otherwise you'll get a reading of 0. This is what happened to me and caused some amount of initial confusion.