If you are having trouble with a specific, legitimate account, you might want to try reaching out via a mutual friend rather than trying to bypass privacy settings.
Legitimate monitoring or parental control tools, such as mSpy or Parentaler, cannot bypass Facebook's core privacy settings to view a locked profile without appropriate access. They work on a device you manage with consent and can't pull private data from someone else's account remotely. how to see locked fb profile work
They ask for your username and password. If you are having trouble with a specific,