When I suggested using heading styles and such, the idea there was to make this a 30-second fix in the layout phase, rather than having to scroll through the document, inserting manual page breaks (a bad idea to use in general), inserting images by hand, and so on.
LibreOffice: page breaks on recto settings for the Heading 1 style
Generally speaking, layout and formatting should be handled by the stylesheet. One just needs to get a styled document out of Scrivener, which is where the majority of the compile setup work should go, disable all of the “page break” insertion in the Separators pane (good for quick-and-dirty proofing, problematic for actual final design), and then once the document is loaded up in desktop publishing software, a template or stylesheet is applied to the structure we’ve given to the text, and seconds later you have a 90% finished book. The rest is mainly going through page by page and fixing awkward lines, widows and so forth. It’s not unusual for that phase of the project to take a week or so—and for obvious reasons you really want to be doing that in page layout software. That’s only way to do it.
Same goes for ToC—that should be inserted by the DTP, from the heading structure. The thing in Scrivener is just for quick proofing. I wouldn’t even use it for that honestly, it’s so easy to insert a ToC in a word processor.
Images should have styles on them, so the same sort of treatment we’ve given to headings, only now to generate page breaks that only appear on the left side of the page, from the stylesheet, not as manually inserted breaks and so on, and probably a break after the caption if you want full-page images on the verso.
So I guess overall that’s the tactic I would strive for in Scrivener. Think less about formatting and more about giving yourself a solid skeleton on the text so that styles can handle all of this dirty work for us quickly and in a procedural fashion. Maybe even consider something much simpler to start from like a manuscript format. There is a reason publishers ask for a basic setup like that: it’s easy to design from a standardised and abstract declaration of intent rather than something highly formatted already. With a tuned workflow, a compile Format paired with a stylesheet in LibreOffice, one can be quite efficient with this part of the project.