Unable to Edit Contacts; Personal name changed to Company name in Already Sent Email Threads

After recently syncing a new iPhone SE with my 2018 MacBook Pro I am having an frustrating time trying to edit my Contacts. I've never used Siri but nevertheless she appears to be conflating some details, even my previous email headers, where headers on email threads I've already sent under my own name have been inexplicably replaced with my company name (listed separately in my Contacts). And I am not able to edit Contact cards without something preventing the edit and the card disappearing into cyberspace after typing one letter, only to reappear jumbled and partly edited. What used to be a simple task has become impossibly difficult.

I wonder if anyone has experienced a similar problem or has any suggestions as to what is going on and how to fix it? Thanks.