Firstly, let me apologise - you DID zip up your project and attach it to the first post; it’s just that by the time I read post #11 (possibly a few days later) I’d forgotten!
This one’s simple, I think:
You’ve given Dorico 13 flows, but only a couple of them actually contain notated music. The remainder just have an empty placeholder bar, but Dorico’s still seeing that as music that must be displayed. You can override that by going to Setup mode, selecting your “Full Score” layout (right side), and then unticking all the flows (bottom panel) that don’t contain music.