A legacy method of searching the exact process which locks the specified file.
Use ExclusionFolders.txt and ExclusionProcesses.txt to speed-up the process.
Allows to find the exact process pretty quick via Restart Manager API.
Run the application with a specified file to unlock it.
FileLockedBy.exe myDocument.docx
Register the application

Navigate to a locked file which needs to be deleted

Do mouse right-click on the file

Click Unlocker in the menu

Click Unlocker once again to be sure the file is unlocked

Delete the file

PROFIT!
Microsoft.Win32.Registry is used due to .Net core limitations.