I find my pop socket makes the back tap iffy. I’ve also tried the Apple Watch tap, which does work, but both only work (IIRC) when the phone is already unlocked. With my old OnePlus phones I could double-tap the power button while the phone was coming out of my pocket and have the camera ready as soon as it was up in my hands ready to go. I’m not adept enough with the iPhone’s swipe on the lock screen to do the same thing smoothly.
Probably the feature I miss the most, honestly. It’s SO good for capturing things as they were happening.