Did you actually back up your phone→How to back up your iPhone, iPad, and iPod touch - Apple Support
The backup contains your app data, but not your apps. When you restore your phone from a backup your iOS settings and app data are restored, then your apps are redownloaded automatically from the app store. But you must restore a backup to restore your app data.
iCloud+ has 2 independent functions. iCloud backups, and iCloud sync. It’s confusing because they both have the same name prefix. But they have no connection with each other. Go to Settings/[your name]/iCloud. You will see a bunch of switches. When you turn on a switch that data type will sync to iCloud. If you do this on multiple devices that share an Apple ID the selected data will sync to all of those devices.
You can also turn on iCloud Backups. This will back up your phone every night if the phone is plugged in, connected to Wi-Fi and locked.
But note that anything that you sync by the first method will be excluded from the iCloud backups.