Here’s my take on this.
I can see both sides of the argument for using different methods. Since you’re both on iOS, the most integrated way is often through iCloud. If both iPhones are signed into the same Apple ID and have Messages in iCloud enabled, texts will sync automatically across both devices. The benefit is that it’s a native Apple feature, requiring no third-party software. The downside is that it also syncs contacts, photos, and app data, which might not be ideal.
Alternatively, dedicated monitoring apps offer more granular control. These apps are designed specifically to capture text messages and other activities. They typically require a subscription and installation on the target device, but they keep the monitored data separate from your own phone’s data. It really comes down to weighing the simplicity of Apple’s all-or-nothing ecosystem against the focused features of a specialized tool.