Here’s my take on this.
I can see both sides of the argument when it comes to monitoring methods. On one hand, using a dedicated monitoring app can give you a comprehensive view. These tools are often designed to capture detailed activity, such as direct messages, liked content, and time spent in the app, providing very specific data points. This approach offers a direct window into the usage you’re concerned about.
On the other hand, you could start with a less invasive method. Since you have access, you can check the iPhone’s built-in Screen Time feature. It won’t show the content of conversations, but it will give you a clear breakdown of daily and weekly usage for TikTok. This can provide a good baseline of her activity levels. It’s a trade-off between getting a high-level overview versus a granular, detailed log.