iPhone system data filling up device after iOS 26 update

I know many will probably disagree. But such a big update from iOS 18 to iOS 26 should be done as a "clean" update. I personally don't see the point of iCloud Backup anymore. All your photos, files, contacts, etc. are continuously backed up, and it's automatically downloaded when you sign in with your Apple Account. Apps can just be downloaded again in the App Store.

The only advantage I can see is that the wallpaper and apps are in the same place on the screen after you restore from an iCloud Backup. But often you have to sign in to all the apps again anyway.

Here's how I do it. I make sure iCloud is up to date, so that all photos, files, etc. are synchronized. After that, I sign out of my Apple Account. Then I choose Erase All Content and Settings. When the phone is restored to factory settings, I connect it to my Mac (can also be done from PC, iTunes), and then I do a restore, where everything is wiped again and the latest full update is downloaded and installed.

Once that's done, I set up the phone as new without a backup. Then I sign in with my Apple Account, so that photos, contacts, files, calendar, etc. are synchronized back to the phone. Then I download the apps I use again from the App Store, and set them up one by one.

That way you get a clean start. By using the backup, you drag everything, including your problems, onto a new software - or a new iPhone. It can be time-consuming. But in return, you have an iPhone that just works, and you get rid of all the system data that has accumulated.