I’m not gonna parse your logic for you, but here’s what you need to know:
Conditions in a single search are logically ANDed together. To do an OR condition, set up a search1 with the left hand OR conditions and a search2 with the right hand OR conditions and :merge them together.
So construct your search expressions with this in mind. With the parentheses “experimental” feature turned on you could even write a very complex search in a single expression builder expression.