All Apple products contain builtin blockers for tracking. Apple Devices also prevent "cross tracking" which denies apps you are not using from seeing data from other apps. This is more recent in the last year or so, costing Facebook BILLIONS of dollars in lost ad revenue.
I suspect this app you and others use is simply using the information supplied by the Apple Device which in itself is blocking all types of nasty tracking and its all free with the device.
WIth that said, Apple devices do not block all ads.
This is what your Apple Privacy Report looks like on a Mac Desktop. If time I will post the iPhone one too. Keep in mind I routinely delete my cookies and history or the numbers would be MUCH higher.
View attachment 185098
View attachment 185099