If your missing device doesn't appear in the Find My app or at iCloud/find, you didn't turn on Find My. There's no other Apple service that can find, track, or flag your device for you.
Summary. Apple's Find My network can be used to track a lost or stolen iPhone, even if it's been turned off or offline. For this to work, Find My Network will need to be enabled on the iPhone before it's lost. The feature is only available on the iPhone 11 and later models.