ST offers only:
- geo-fence based on mobiles and to be honest, recently they fail big time, whatever Android or IPhone.
- arrival sensors you also concluded are not reliable. I guess they should rename them stay sensor rather than arrival as they fairly work when they stay in your hub area, good battery life. But if you happen to spend 8 hours outside a day, the autonomy just get ruined in few weeks and the detection is anyway inaccurate.
So I would rather go for a wifi device of any type and an IFTTT associated setup that pings an event when it connects to your wifi network, It will additionally have larger range than your arrival sensor.
Or this 