Accessing hardware data (CPU usage/temp, GPU usage, temp, memory free/used, etc)

I have been searching for software that provides a sensor panel much like what is provided by Aida64 on Windows. Since I got no luck, just text based dumps of statuses, I decided to write my own.

So first question: is there a DLL in the OS that exposes the sensors at the hardware level? NOTE I'm talking code NOT some script to scrape.

(I'm a retired C# developer and this is the first program I will be writing on Linux)