> What I'm missing is the depth, the particular knowledge of these musicals.

I get it. Well, even so, I don't really know enough about music, let alone your tastes, to understand what you might appreciate. But I suppose if I just gave you five of my absolute favorite American musicals as recommendations, I'd have to go with Oklahoma, My Fair Lady, 1776, Oliver! (or is that English?), and Into the Woods. That covers mostly the later ages of American musicals; earlier, maybe 42nd Street and The Gay Divorcee. I'm trying to think about the stage, rather than the movie versions that have been made of nearly all the great American musicals, but the fact is that the movies are often the best ways to see them.

On the Film-Lover's Check List, the "Genres" page has a list of the 50 film musicals I felt were the 50 most essential musicals to see, were one to make a survey or study of the history of filmed musicals. Because of the extensive overlap with the stage, you might find that helpful resource if you're interested in delving into the particulars of American musicals.

Again, I am doubting that I'm being much of a help to you, but that's the best way I can answer your request for recommendations.