My first smartphone (because 3G is being turned off soon) is a Motorola G Power 2021, with the lowest resolution, slowest processor option available (less pixels in the same form factor --> less power consumption, and I'm old so little pixels are too small for me to see anyway) It runs for multiple days on a charge. It will serve as a hotspot, if you want it to.

I'm using Mint Mobile, for $15/month.

I uninstalled Twitter, Facebook, etc. I did install AdBlock browser. I've disabled all notifications except for calls and texts, so that my family can reach me.

I almost never check email, and the same is true on the phone.