Hmmmmm. On my iPhone X, having background refresh on doesn't seem to help. 90% of the time if I walk up to the car with my phone in my pocket, I press the door handle and it is still locked. Then I fumble for my phone and have to wake it up, not unlock it, or open the app, but at least have the screen pop on for the doors to unlock.
If the phone worked like the FOB based passive Model S door/locks, I'd love it. But now, if I don't want to be embarrassed showing the car, I always have my phone active.
I'd say this, and not having auto opening/closing trunk are my two most missed features. First world problems.