Only apps with root can see the private app data in /data/data/ or /data/user/*/ that stores your app preferences, login info, databases, etc.

Without root, you can have some extra permissions by installing Shizuku - you will need adb to grant Shizuku that rights (this app is used to give those permissions to other apps supporting Shizuku - check those here). For example Swift Backup works best with root, but without it it can still backup at least external app data (located in Android/data)

You used to be able to do proper backups via adb, but now you rely on app devs using proper backup methods via Google drive thing, and very few of them do.