My wife and I have a Family Plan and we each had the following vault setup:
This worked but we found it annoying to have to remember to move (and not copy) things into the Shared vault and difficult to remove old Shared items since ownership was fuzzy. And because neither of us cares if the other can see each other's items I moved to the following for both of us:
This way we'd each view/add/edit in our own vaults and only occasionally look into the other's for an item.
1Password Version: 7.8.7
Extension Version: Not Provided
OS Version: macOS 11.5.2