I highly doubt any carrier would offer this, especially with the current adoption being where it's at. You'd be better off using your phone's capabilities to restrict calls to only your contacts.
This is what I do, and feel is the only solution now. Phone always on DND/only allow contacts to ring. A whitelist approach if you will.
This is great and all until there’s an emergency and someone is trying to reach you.
Yeah, it's less than ideal, but this is the future that the lazy carriers have brought us to. Hopefully, someone trying to reach me in an emergency would have the brains to send a text.