Apple calls two different things 'Find My Phone', the phone's location tracking of itself and then there's the entire network of Apple devices across the world that constantly monitor for the AirTag's Bluetooth Low Energy beacons allowing you to find the AirTags (and any attached valuables) anywhere in the world.

There are many things that let you ask your phone where it is (or have it report it's location to a server that you host).

There is nothing that matches the worldwide network of Apple devices which are listening for your airtag's BLE beacon.