I never said you are breaking any law, so please don't confuse my comment with anyone else.
You do as you see fit with your family. Here is a link from Apple about creating an Apple ID for children under 13, which you can either follow or not --> Get an Apple ID for your child - Apple Support
As to the merged phone calls, if you are unwilling to separate your family, you'll need to accept every person on your Apple ID will have access to ALL your data. And while you may think you have configured, for example your text messages to be separate from your spouse or children, which you can easily do, you are not likely aware, they can open Settings > Messages > Send and Receive and check your phone number or anyone else's phone number tied to your Apple ID and start reading your messages without your knowledge OR approval. And this is by no means new with iOS 17.
So, if they can read your text messages if they want, why would you be bothered about them seeing the phone numbers you call or receive calls from? You are in essence permitting the entire family to have full access to everyone's data on every iPhone.
You take care.