Many modern computers, especially from major manufacturers like Dell or Lenovo, have the Windows product key embedded directly in the computer's UEFI/BIOS firmware. If a user extracts this key and posts it on Pastebin, it is useless for anyone else. This key is digitally signed to work only with the specific hardware configuration of the original machine, primarily to help that user reinstall their own licensed version of Windows without needing a sticker.
: Microsoft’s activation servers frequently flag and blacklist keys that appear on public forums or repositories, rendering them useless for future use. The Risks of Using Public Keys Security Vulnerabilities windows 10 product key pastebin
Given the significant risks, it is far better to pursue one of these safe, legitimate paths to getting Windows 10. legitimate paths to getting Windows 10.