In short I want an automation that says “when an item is created and only if the items content matches the content of an existing item in this column then replace the existing item”
This would help me with boards where I have users creating new items which frequently supercede the preexisting items. For me, I use a column such as the email as a unique identifier. You could also use the person column as well. When the same person creates a new item, I want the two items to be treated similary to Monday duplicates, where the new data would overwrite the old data, but any data from the old item not captured in the new would remain.