First off, iOS =/= macOS, iOS is what's used in iPhones, and macOS is for Macs.
In my case, automation/scripting and setting up custom hotkeys or gestures to do various things, is a key requirement for me in any OS. In Windows I use AuthHotkey and PowerShell, in Linux I use ydotool+Fusuma and bash/Python, for macOS it's Keyboard Maestro and zsh, finally on Android I use Tasker+Edge Gestures and bash. Unfortunately there's not much of a choice for iOS; there's Apple's own Shortcuts feature, but it's quite limited in what it can do (although admittedly the limitations are more due to the nature of the OS itself).
To give you an example, on Android I've got a Tasker profile which automatically announces the name and artist of the currently playing track on Spotify, just like how you'd hear on a radio - this is super handy for me as most of my music listening is done when I'm in the shower or doing other chores and don't have my phone handy - and thanks to the announcements, I can make a mental note of what was playing, and if I like the track/artist, I'd look it up later on. I can't picture how to do this on iOS. There's a bunch of other Tasker tasks as well which have no equivalents on iOS, as well as nothing similar to the Edge Gestures app which allows me to map custom gestures to various apps/actions/Tasker tasks.
My other requirement from an OS is the ability to freely install apps of my choice without being restricted - and iOS again fails in that regard, due to lack of sideloading. On Android, you can find a ton of indie apps on github or alternative stores like F-Droid, which aren't available on the Play Store - and these sort of apps will never see the light of day on iOS for various reasons. For instance, one app that I really like is Shelter, which is an opensource app that allows you to create a second user profile, which is handy for multi-accounting/testing/separating your work apps etc. AFAIK, there's no such app for iOS. Another Android app that I like is App Cloner - this one allows you to modify various bits of the cloned app for privacy - you could for instance spoof your location, or set the app to use a proxy server of your choice (or a list of proxy servers). Then there's AdGuard the app, which allows system-wide ad blocking with HTTPS filtering (which you can't get with a simple DNS-based ad blocker). I could write an entire essay about similar limitations, but yeah, long story short, iOS is incredibly limiting for my use cases.
Thankfully, macOS is nothing like that. Yes, I can't have custom themes like Linux, but I can at least automate pretty much everything thanks to third-party apps like Keyboard Maestro, and have the freedom to install all my favorite CLI tools via Homebrew. My main issue with macOS is it's shoddy support for gaming, but that's where my Linux laptop/PC comes into the picture. :)