There are plenty of reasons that people use iOS over Android, but if you know me, you know that I personally use Android.
The main 2 reasons I use Android is customization and open-source. iOS has gotten much better at customization with the past few updates but when I switched from iOS to Android it was during about iOS 12 days so back then it wasn't nearly as good as it is now. Although I will say every year Apple makes it harder and harder to hate on their phones, but I digress. I personally use a Samsung phone and with that comes the "Good Lock" suite of apps (if you don't know what Good Lock it and you own a Samsung phone I HIGHLY recommend looking into it) and by using Good Lock I can change just about any aspect of my phone that I'd like.
The other reason I use Android is the fact that it is open-source. I prefer open-source software for a multitude of reasons, one being security. I don't use the term security in the way that is like "My phone is more secure than your phone" cause that simply is not the case, I use the term security in the sense that I have the security of mind of knowing that there are individuals out there who read and understand all the source code for Android and if they found anything worth looking into, they would. And who knows, maybe one day I will read all the Android source code (I won't).
Another reason I use Android is the fact that you can side load apps. Yes while you can technically do this on iPhone, it's not nearly as easy, and that's the reason that if Google decides to stop the ability to side load apps onto Android I would probably riot. I can get all kinds off apps that would most definitely not be allowed on the Play Store but are on F-Droid or whatever.
It mostly all comes back to the statement that my phone is my phone and I should be able to do what I want with it. That statement is becoming less true these days with really anything but still, if I buy something, I should be able to do whatever I want to said thing.