To troubleshoot, I’d create a virtual presence sensor for her and create two routines to mirror the ST app location to the virtual presence sensor. That way you can tell whether or not ST geolocation is actually working.
Also, I’m not familiar with iOS battery saving methodology, but on Android there are settings to prevent an app from being put to sleep to save battery. Make sure that ST will always run in the background and not put to sleep if that is available.
I also had bad reliability with ST app location and was using Life360 until Jan when Groovy smartapps were discontinued. Tried ST app location again, but still unreliable. I’m now using Alexa app location and it’s been very reliable. I posted about my setup here.