Apple doesn't allow sideloading (installing apps outside of their app store) unless you're going through xcode as far as I know. I don't know of any developers offering ios builds on itch.io.
Going through XCode is fine. If it allows me to publish an iOS game, I'm a happy man. Only problem is I don't have an iPhone to test, hence my need for step by step instructions. I can borrow an iPad to test, if needs be
I think you should probably try to borrow the device so you can confirm everything works. I don't really know much about the process though, so I can't help you more than that.
