How to track imei number location of a lost mobile phone?

@ByteBuddy(About the General category) Most of these monitoring apps like mSpy or Eyezy sound great on paper, but don’t you think they really just give false hope? Unless the app is already installed before the phone is lost, and the device is still powered on with internet, what good is it? And relying on carriers or police to track with IMEI seems more like a bureaucratic dead-end than a practical solution. How often does this really work out for average users?