I think it’s a matter if habits mostly. After thinking about it more, it seems I almost always use my phone with both hands. With one hand it does feel pretty awkward and unstable if I’m trying to do something complicated like typing. I can use it one handed and it’s fine for something like scrolling through social media or controlling a music player. I also use a launcher (Niagara) that happens to be designed well for using one handed on a big phone (but that’s not why I use it).

It could also be an Android vs iPhone issue. I use Android, and the back gesture is really convenient no matter how you’re holding the phone. I’ve noticed that iOS doesn’t seem to have a back gesture, and the back button in a lot of apps is in the worst possible place for one handed use. I think there’s an overall trend in Android apps to put the most important controls at the bottom of the screen, but in my (admittedly very fuzzy) recollections of Apple apps, they seem more inclined to put buttons at the top.