Hi @mgalleher ...
Interesting question! I do not recall ever seeing an option within Canvas Studio where you could move (drag and drop) questions on the timeline that have already been created. That being said, in my mind, it doesn't mean it hasn't existed. I did take a look at this Guide, How do I create a Canvas Studio video quiz? - Instructure Community - 1682. I am able to take a look at the edit history of Guides, and I went back to the middle of 2021, and I didn't see any references to being able to move questions to another area of a video's timeline. Also, I did try this in my own sandbox course, and I was unable to move questions along my video's timeline. ☹️
Sorry that I do not have better news for you at this time, but I hope this helps to answer your question.