Bob, Like others have said, android might be your solution. I have a Samsung S7 edge and I've never run out of juice in a day. I charge it overnight at bedtime.
Someone else mentioned, on an iPhone, you can close your open programs one at a time by double clicking the home key and then swiping up on each open program to close them. You might have 20 open programs....that's a lot of swiping. On android there's a "close all" button. One click and you're done.
It's a good habit to at least once weekly, power cycle your phone. Not only will it help restore corrupt files but each time you do it, you're updating your carrier's network on your phone.
I had a Samsung Galaxy Note 5 for my last phone and it lasted 3 years. Phones, like computers, become slower over time partly because OS updates by design, are written for current technology and older model's processors and memory struggle to keep it running efficiently. Anyhoo, my Note 5 still works fine, I've relegated it to my workshop and use it to run Pandora over the wifi.
I have a Macbook and an iPad, my .02 is Apple's gone by the wayside when Job's passed away. I'm seeing as many OS updates, if not more, than Windows since he passed. It seems like that anyway.