How can I share and manage a combined Contacts list with my spouse using Family Sharing on Apple devices?

I was an Apple employee back when .Mac came out so have a .Mac email address. I bought content using that a single AppleID over the years - and that was fine until you added Health and other features that now assume individual AppleIDs. Your design of FamilySharing is a huge mess and Contacts is the worst.

My wife and I have combined Contacts of nearly 900 individuals and businesses. We use Contact Groups to categorize my friends / colleagues vs hers - but most contacts refer to people/businesses we both know. Because FamilySharing doesn't support sharing Contacts we have been forced to used a single AppleID.

I've even considered setting up an LDAP server at home to store our contacts - and hope that Contacts apps would store a cache when disconnected. But do try that I need to use Directory Utility according to Configure LDAP directory access in Directory Utility on Mac - Apple Support

But my new M4 Mini doesn't have Directory Utility in the Utilities folder, nor is it in the App Store.

Uggh!

FamilySharing needs to have an architecture - that tracks how real families work. New members are added and share their Family's content. They become adults and leave - taking a copy of Contacts, etc. but disconnected from the Family. Same with divorce. And need to merge new family members in, such as blended family - with their calendar, contacts, etc.

Please fix this mess!

[Re-Titled by Moderator]