I'm on the younger side, and I tried "no smartphone" for privacy and peace. I activated an old phone we had in the house. Result: I liked it, but it wasn't compatible with the modern age. It didn't have internet (which did not bother me), but it also didn't send/receive picture texts. You don't realize how dominant that form of text has become until you get multiple "cannot process text message" notices.

SO, I compromised. I bought a cheap smartphone - and made it dumb. I removed the internet from it. I never activated bluetooth. In addition, the phone has a removable battery.

I figure that it is sort of secure - because it doesn't have my internet search history. In addition, I can always remove the battery when I want to be extra safe. I do try to keep it in a Faraday Bag where possible.