How do I make my Macbook Pro control email sync and not my iPhone?

Since upgrading both my iPhone and Macbook Pro to new machines and OS the iPhone seems to control what emails get deleted on both machines - and seems to do a highly inconsistent job of it. I would really like to go back to letting each machine decide what emails to keep and what emails to delete.

Short of that, I would prefer that the MacBook Pro is the controlling machine in the sync, not that iPhone.

Why is this all messed up now? I hate it when upgrade break something that was working just fine.

Eric