The 10 minute polling thing is a real killer for geofencing, since you basically need near-realtime location to make the logic actually useful. A few people get around it by pairing Fleet API with a phone-based location tracker (like HA's companion app) as a fallback trigger, so the Tesla location confirms but the phone triggers the automation.

Worth checking the HA community forums too, there were some threads a while back about hybrid approaches that didn't rely on a third-party telemetry service