Make Sure to Update: iOS 18.3.2 and macOS Sequoia 15.3.2 Include Important Security Fixes (tvOS & visionOS too!)
Make Sure to Update: iOS 18.3.2 and macOS Sequoia 15.3.2 Include Important Security Fixes (tvOS & visionOS too!)

www.macrumors.com
Make Sure to Update: iOS 18.3.2 and macOS Sequoia 15.3.2 Include Important Security Fixes

Settings > Apple Intelligence & Siri > Apple Intelligence [OFF]
The real answer? Buy a phone older than the 15. You'll never get on-device intelligence. My 13 Mini takes great pictures, performs perfectly, has great battery life as a non-gamer. And it should get at least 3 more years of iOS updates (maybe more? phone specs have really leveled off).
Anything newer, Apple and Google will start pushing intelligence on you simply because your phone can do it.
You could try GrapheneOS as well on a recent Pixel.