Anything using mobile phone presence will have a fairly broad radius because you never know which cell tower it’s going to be using.
I myself have written a number of times over the years about my specific issue, which is that I don’t drive. I use a wheelchair and when I arrive on the bus, which is halfway down the block from my house, it can take some of the bus drivers five or six minutes before I’m actually off the bus and on the way to the house. I don’t want my door to be unlocked for that entire time, and since it has an autolock on it, it typically would end up relocking itself before I actually got to the door.
I have a very specific range that I want to manage, which is basically the length of the wheelchair ramp at my front door. I don’t want the door to unlock until I reach that point.
While there are multiple ways to handle presence, if you really want a narrow detection zone, I have found the most effective are based on Bluetooth. I personally use an iBeacon Detected by an iOS device.
Here’s the faq on that method:
FAQ: IBeacon Short FAQ (2024) (US AND UK)
There are some people using the method with android phones, but I think it does work best with iOS devices.
Some people have had good results by basing presence on their own Wi-Fi router detecting their phone. For me, that distance is still too wide, so I haven’t played around with it much, but it is another option you can try…