A couple more ideas I've thought of.
-Better third party monitor support. This mainly applies to the Mac and iPad, maybe the iPhone if it gets better external display support. I have an app on my Mac that lets me adjust brightness and volume on my non-Apple display. Why can’t this just be baked into the OS? And let me connect a touch screen monitor to my iPad/iPhone. For the iPad being a touch-first based OS, it's kind of weird that I can’t use a touch screen monitor with it. If Apple builds one with full Apple Pencil support, I'd consider getting one. When I was still a Windows user, I used a touch screen on a movable mount so I could use it like a regular monitor, or I could adjust it down and use it as a large touch screen.
-Make the "Speak Screen" control better on iPhone and iPad. I'm not even sure if this is on the Mac or not. Sometimes when reading I like to use this, it helps me comprehend things a little better especially when trying to learn something new. Most of the time, it works fine in the Apple Books app. It will use Siri's voice to read along, and automatically turn to the next page and keep reading. But, it's buggy. If I have it set to highlight the words as it's reading them, sometimes it's out of sync. Sometimes it just stops reading instead of turning the page. I can just get the audio book version, but I don’t believe there's a way to listen and read at the same time - though I think this is possible in the Kindle app if I ever switch to that. If I’m using it in CarPlay to read to me while I’m driving, the audio (Probably intentionally) cuts in and out like a bad radio signal.