Hello there,
I'm Gowtham, I'll be happy to help you!
I apologize for the issue you are experiencing. Please be assured that I will do my best to provide a satisfactory response and assist you with resolving the problem.
I can understand your concern, as you have tried a number of different methods to fix the Diagnostic Policy Service issue, but nothing has worked so far.
The corrupted Windows files can cause this issue. Try running the System File Checker to resolve this issue. This will scan your system for corrupt files and attempt to repair them. Here's how to do it:
=> Press Win + S to open the search box.
=> Then type "PowerShell" and select Run as administrator from the right pane.
=> If UAC appears on the computer screen, click Yes to continue.
=> In the Command Prompt window, Input this Deployment Image Servicing and Management tool command and press Enter:
DISM.exe /Online /Cleanup-image /Restorehealth
=> When the first Scan is done, type this command in the Prompt’s window and press Enter:
sfc /scannow
The scan may take a while to complete, but once it's done, restart your computer and see if the issue persists.
Hope it helps you. Please let me know if you have any further questions or concerns.
Thank you!