I've been forced to use iOS for my work phone and it is absolute dog shit... it feels like Android from 10+ years ago. The lack of customization and dumbass work flows drive me crazy every day.
So many screens in different apps. make you reach way to one corner or the other to go back a screen. In Android, back is one motion that can be done anywhere from any edge. And that behaves consistently across every app. In iOS some apps behave differently, even the same app with a different screen will handle the same gesture differently. It's an absolute shit show.
Want to open my app list, I just swipe up from anywhere on my screen. Want my notifications, swipe down from anywhere on my screen. In iOS I have to perfectly hit the top edge and slowly drag it down.
There are plenty of other reasons.
Access to the filesystem. Wtf! Lmao. I download a PDF and can't just open it? I have to basically share it with the app, it's so dumb.
Split screening apps.
Complete lack of customization. The launcher is ass.
Horrible keyboard and the one I like, SwiftKey is completely neutered and lacks the customization of Android. And some apps will use the apple keyboard even though I changed it to use Swiftkey. Again, no consistency.
Messages will pop a notification then when I open the messenger app they are not there. I can read the message in the notification area, but there is a period of time that it doesn't display in the actual app. Lmao. Dog shit.
Many, many other things.
Apps and services dying to backgrounding like the hotspot for one will just stop working after a certain amount of time.
Want to know how I change my brightness in Android? I just slide across the status bar in any app on any screen.
When I want to turn my flashlight on, all I do is hold my power button down for 3 seconds. Don't have to turn my screen on and click anything.
So many things. The settings in iOS are also a joke and the way they are organized, I just hate everything about it. It feels like I'm running Android from 2010 with less customization.
I think sandboxing the filesystem by default is a good security measure. For Android it makes sense since you can sideload an app and that always carries risks. I think it can be improved on the UX side without compromising much on security but that is not my expertise. And note that I have not used iOS devices in ages too so I don't know how they handle the filesystem now.