How can I fix Message confusion on shared iPhones?

My wife and I share an AppleID on two iPhones (11 and 13) and two iPads. Messages are all screwed up! Followed one link here,

iPhone thinks I’m my husband - Apple Community

where directions said go to Settings > Messages > Send and Receive.

Had to search on Messages to find that folder in Apps.

When there, I see that both my phone number and hers appear. I am able to check or uncheck the items in the list, but not add or remove any.

Still stuck! Help appreciated.

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