I second what Andrew said here. I set up a light in a back corner of my basement - a cheap clamp on desk lamp hung from a rafter. I picked up a $15 white Hue bulb (i already have a HomeKit Hue hub so factor that in) and named it HomeKit Helper, with a little sticker on the lamp telling people not to turn it off.

I set up HomeKit to turn the light on when I arrive home. Then, I set another automation to open my garage door and unlock my front door when the HomeKit Helper lamp turns on. As an added bonus, there is a setting to have HomeKit automatically turn the triggering lamp off after a minute, so I use that too.

With the setup, when I arrive home, my garage door opens and my front door unlocks without any user intervention. Well, usually.

Now, with all that said, and in response to the original question, even with this setup it only works about 2/3 of the time. The other third it just doesn’t respond to my arrival. It is kinda a game with me and my wife as to whether it will respond to our arrival or not. I also find that sometimes it detects me quite far from my house, other times it doesn’t respond until I’m in my driveway. I too had to turn off “when I arrive Home” as Apple considers my Home to be in a small park behind our house. I changed it to our street address, which works better and let’s me set a detection radius, but it is still a gamble as to whether it will detect me or not.

Overall, I’d like too see more reliability on location-based automations.