(if this Topic is too soft, ie not strictly related to cracking issues with Apple stuff, I won’t be offended if it’s deleted)
If I read @tommy ‘s intent correctly , I‘ve set my iPhone Wallpaper to black, and icons to monochrome, not as a way of reducing its appeal and to reduce overuse, but as the joy is gone and the need is much less with current lifestyle. There are too many reasons why, but I suspect I’m not alone in actively reducing use/connectivity.
(‘iPhone’ in the Topic Title in this case refers not to just hardware or software but the whole package as a tool)
iPhone functions I haven’t been able to easily replace with pen and paper include: Weather info; Signal; Word games; emergency reporting; maps; translation dictionary; multiple easy to set and reliable alarms; and Mail with a free non-Apple account for the occasional need while out and about. Oh, and as a mobile phone ;-). I do have some other Apps on there but they are only for convenience and can be easily replicated with physical objects when in reach.
I have a general inclination to ‘right tool for the job’ and from original iPhone on it has been right and life-enhancing, but these days it’s almost too much. So my goal is not so much ‘iPhone Zero’ you might say, but ‘iPhone Minimal’, in a way that makes it again life-enhancing and not a drag.
I also have it logged out of Apple Account and App Store and set to Low Data Mode to see if the reduced internet usage hinders usability (so far it hasn’t). If not I can save plenty of Quid on data costs over the years.
Happy to explain any of these or other choices, maybe my reasoning is off on some of them and questions can help get it just right. Hope the topic is helpful to others.