That sounds about right. FAANG companies usually need generalists because teams are so big and scopes shift often enough that the ability to pinch hit becomes an important trait. Or if they need specialists, they usually need [company]-flavored specialists, which you can't be if you didn't come from internally.

In my experience the managers usually have a pretty good idea of what work they need filled, but because the hiring pipeline produces generalists, there's some after the fact matching of interest and experience to the available list of projects.