Have a look at [UPDATED] iPhone WiFi Presence Sensor. You can ignore that it says iPhone in the title as it works fine with the Android operating system. It basically causes Hubitat to ping a specific/reserved IP address to see if it is present. It can serve as the bases to help with determining overall presence or potentially serve your needs. I want to say the ping is every three minutes or so and is user configurable.
Lots of us combine the WiFI presence app with [RELEASE] Combined Presence to help determine overall presence in a location.
