Q: Stop Shared payment

Hi

Follow the instructions here to stop Family Sharing and disband the family group:

Leave Family Sharing - Apple Support

You can't stop one without the other.

You may wish to arrange for your family members to credit their accounts with gift or store credit.

When they have gift or store credit, that will be used first whenever they make a purchase. Only any remaining balance will be billed to your account.

More information:

Family purchases and payments - Apple Support

I'm afraid that no-one here can tell you anything about Apple's unannounced plans (this is a user-based community).

You're welcome!

If you would like to send feedback to Apple, you can do so here:

https://www.apple.com/feedback/