Let's start with something simple.
Previously, when you activated Windows, the process "called-home" to Microsoft to register your product-key.
If you reinstall Windows, while having an Internet connection (WiFi to your ISP's router, or Ethernet cable to your ISP's routers), it will again "call-home" to retrieve the registered product key. So, install Windows WITHOUT any connection, so that it cannot try to activate.
However, newer computers have a product-key embedded in the motherboard. The Windows installer will retrieve that product-key, and will automatically use it. I do not know of any way to prevent this type of activation.
Note that when installing Windows, you must click "I do not have Internet", to avoid the request to supply your Microsoft ID.
You will perform a "limited install", and you will create a "local" account that is NOT linked to any Microsoft ID.