let's assume you are using Windows, you can always use 'Find my device'
The last time I tried it, it was off by 4 houses, so it is definitely worse than Apple's Find My system.
But it could give an idea of whether you left your device in one building or a different one if those buildings are large enough.
From what I've read, AirTags don't use GPS, all they do is connect to other Apple devices via Bluetooth, and those devices send their location (which is fairly accurate) and the AirTag's ID (which is encrypted) to Apple servers.
This means AirTags are useless if there are no Apple devices around.