I wish it were that simple!

There is no good way to back up an Android phone, unfortunately.

By “good” I mean in such a way that you can restore it and be back to a 100% identical state with no additional steps. And that you can validate that backup before erasing the source, and without needing an additional identical test device.

ADB backups will not contain your app data. Not much of a “backup” at all really.

Google cloud backups only work for supported apps (good luck finding out which ones support it!), and restoration is only available during initial OS setup. Validation is impossible. The whole process is highly error prone. In all my years using Android, I don’t though I’ve ever seen this work perfectly. It’s an absolute mess.

Third-party apps either require root or will not back up app data. At least on any recent version of Android. (9+, was it? I forget exactly but it’s been many years now.)