After you update, your phone secretly re-scans your entire photo library to build “memories” and search tags. It pins your processor at 100% for days. Settings → Apps → Photos → turn off “Enhanced Visual Search”

Dozens of apps are pinging your GPS 24/7. Constant location tracking is one of the biggest silent heat sources on your phone. Settings → Privacy & Security → Location Services → set each app to “While Using,” never “Always” Kill the ones that have no business knowing where you are

Every app you've ever opened keeps running and reloading in the background, even when it's closed. Settings → General → Background App Refresh → switch to Off (or Wi-Fi only) Your processor stops working around the clock for apps you're not even using.