This is a contrived example, probably not a real-world use case. The kind of issues I am dealing at work is much more complicated, usually involves more than 3

This is a contrived example, probably not a real-world use case. The kind of issues I am dealing at work is much more complicated, usually involves more than 3 or 4 tables, serializers are referred by multiple other serializers etc. There is usually business logic involved as well in the query construction. I understand things can be improved, but it's not as simple as writing few queries by hand. ActiveRecord/ActiveModelSerializer provides good composability, but fails to handle N + 1 queries optimally, which is what I am trying to explain.