My old iPhone 13 is kind if just sitting there, and I was wondering if you have any ideas to use it to do anything cool? Like as a mini display for weather/other kinds of data, any of that stuff. I have a 3D printer, so I could easily print a makeshift mount or stand for it to go on my desk, shelf, whatever.
You are starting from the wrong side - what do you want to do? Where are the problems in your life? Is there someplace/thing where a small screen or camera would help if only you had it? Lights/devices you want to control from a location where this is no switch?
I put a weather station on my home assistant dashboard - but it turns it is never the forecast I need so I google the weather anyway. So from my experience the mini weather isn’t worth it. (I do use my dashboard for other things worth it, but it is a 20 inch monitor visible). Reports are other people in the world have and love their weather station display, ymmv.
Don’t forget to ask your family/roomates. They may have an issue that you don’t see.