What is the most important finding in the pre-orthognathic surgery examination?

I feel like deciding on double jaw surgery isn't just about looking at your face shape, so I'm curious about the examination process.

I've heard that they look at occlusion, temporomandibular joints, asymmetry, and even breathing issues; is that true?

To what extent can the pre-operative examination determine if surgery is absolutely necessary?

I'm also wondering if the diagnosis can differ based on X-rays compared to a CT scan. ㅠㅠ

For those who have undergone the examination, what was the most important part when you heard the explanation of the results?