Thanks for your reply Ramon.
Understood that targetData cant be made available in broadlog but using additional data, it can be made available in outbound transition of email delivery. So for 10 emails sent, there will be 10 entries in the outbound transition. Once email is sent, each of those would generate a delivery log id. This is where I want to enrich my targetData with delivery log id.
Looking up broadlog data doesnt fully solve our use case because we can have same user targetted multiple times and I cant have 1:1 mapping between the two. So I was looking for profile + 1 additional attribute to make relationship 1:!