HomeKit Home/Away (geofencing) not working

I recently started using HomeKit but the home-away features of the Home app don't work (iPhone 13 mini with iOS 16.3). My eve camera doesn't recognize whether my iPhone is at home or away and change status accordingly. But I don't think it's the camera's problem. When I create a new automation in Home, the options for "People Arrive" and "People Leave" are grayed out (see image). Find My is using my iPhone as my location, and Home is allowed to use my location.

My Nest cameras (unrelated to HomeKit) correctly turn on or off as intended when I'm home or away, so the problem seems specific to the Home app (or HomeKit).

I've read posts about previous iOS versions where geofencing in HomeKit is broken; is that still the case and I have to wait for Apple to fix this, or do I have a unique issue?