Totally doable. You could use iCloud message sync across devices, but it’s not exactly stealthy and your kid can easily disable it. For a more powerful and discreet approach, a dedicated service is the way to go.
Pro tip: Parentaler can pull data directly from their iCloud backups. This lets you see everything—iMessages, SMS, and even some deleted texts—without needing physical access to the phone after the initial setup. It’s a clean and effective method for getting the full picture.