IME, You are so right about trying to learn theory without structure!
But once I understood what all the diddly music bits do together in composition I knew better about what to focus on. For me it all hinges on the journey and destination of a composition. I can see that most clearly in simple compositions like folk songs, especially really old ones. I learned about RESOLVE and CADENCE and it all fell together for me....
http://openmusictheory.com/cadenceTypes.html
Then I explored the concepts on a more abstract level:
https://www.coursera.org/learn/music-as-biology/lecture/CGmnm/tension-and-resolution