If you are approaching from the rear of the car, there is a known "dead spot" back there where the antenna doesn't see the fob or mobile key. It varies from car to car, though, because mine does just fine when I walk up from behind most of the time. From the front a few people have reported issues as well. But that always triggers fine for me as well.
Long story short, this is a lot more complicated than it looks.
The longest I ever have to wait is a second or two after I've actually gotten to the door. Most times, the door is already open by the time I reach it. But plenty of people report having to wait much longer.
It's wireless. It's Bluetooth. There's environmental factors. A combination of software and hardware. Interference. Which means it's a very tough nut to crack. And likely it will never be fully resolved for some people due to the hardware. It's just not an ideal design.
One hopes Lucid thought of all this when they designed Gravity. And hopefully any of those learnings will trickle over to the Air in a future hardware iteration.
Meanwhile, for our cars, it may be worth having service look into possible antenna issues? If you are really having that much trouble.