I suspect some of us might have differing expectations when we talk about how reliable the mobile key is, but would be happy to hear otherwise, so I'll be more specific.
Mine always works... eventually. It almost always works quickly if I actually take out my phone and wake it (my iPhone 15 PM) up. I'm assuming it's the iPhone's job to signal the car, and iOS power saving just doesn't think it needs to do that very often when it's in my pocket.
I almost never have to actually open the Lucid app to unlock the car, but that definitely happens sometimes. I don't think I've ever had this issue getting into my car for the first time in the morning, but if I have to make multiple trips to load things into my car, the second or third time it will often sit there with the handle depressed making uncertain car noises as it ponders whether to let me back in or not. I've taken to leaving a door cracked open if I'm just stepping away for a moment. One time that also turned out poorly, as the car decided to lock anyway (all except the open door, which I've never seen before), and then sounded the break-in alarm when I opened the cracked door again.
I never have to enter a pin to drive with the mobile key, and I have only seen the "no key detected" message once or twice in the months since I stopped carrying the fob in addition to the mobile key.
Note - I have automatic unlocking off, automatic locking on. Like many, I'd turn automatic unlocking back on and probably have a better time if it could be geofenced to avoid constant unlocking at home.