We gabbed about this today in writers' club. One problem with the exercise is you can fit many suppositions, any manner of supposition, to a piece of expression (a novel). (Rose colored glasses and all that.)
Lord of the Rings: Frodo can keep the ring OR save the world
... But... Frodo wanted a quiet life in the shire. He wanted neither of the above that you stated. He didn't want either.
And what of Boromir, or Sauron, of Gandalf? Why was Frodo the main viewpoint protagonist? Why not Sam? Or Smiegel? They each have agency and an arc. You can sort through what you think, for each.
Star Wars: A New Hope: (I changed the prompt): Luke can renounce the ways of the Jedi OR use his power to help the resistance
...Luke's moment of culmination, in both IV and V, is when he relinquishes control. For Luke, it is all about giving up any illusion of control, submitting to the force, that things will work out. (And this is the tension in VII-IX). When he shuts down the tracking scope in IV, when he stops attacking Vader and throws his light saber aside in V, it's about saying "I submit." Submission to the force is the theme in those stories. Not control.
The Book of Strange New Things: (I don't know this one.)
You will never 'locate this thread' in all stories, because not all stories are the same. That's good.
Fairy tales, just-so stories, and so on serve a different purpose. Psalms (in the bible) serves a different purpose.
Genre fiction might benefit from outer/inner goals and conflicts, and I love (and grow through) MBaker's thoughts on this, but i disagree that it is the only way to share human experience through story.
So how do you find the twinned goal in an ensemble piece? In a heist?
Simple. You look ... and do the work to figure out what you think in that piece, for each character. Who do they love? What do they want?
In writers' club, we spent a good deal of time discussing Luke's 'want' today. Simply, we decided it is to join the rebellion. But one person said his truest want is control, within his life. I said it was to prove himself 'as good as Biggs.'
The case can be made for any of these. Luke's 'need' on the other hand is to manifest, to actualize, realize his one-ness with the force, which is to say... to leave to the side any illusion of control in his life.
The force, that's the power and director. Luke needs to submit to it.
Is that useful to consider? No idea. Play with it. Decide for yourself.
Simplified, the thing they (protagonists) need is internal. Love. A person. Self esteem. (for Luke, he needs to relinquish any illusion of control... = internal.) The thing they want is external. Saving the world. Joining the rebellion. Being better than Biggs. Money. Winning the cup.
How do you sort it for a different style of writing? You jot down ideas and see if they help, knowing that storytelling is more nuanced and complicated than a binary modality like this.