Creating invisible spacer cards will work, but it adds clutter to the project and requires maintenance. The Content Map helps with that maintenance. When "pinning" is enabled, that should solve the problem. Until we have pinning, I'm afraid using dummy spacer cards is the only workaround for this approach.
Can you make the first banner full width? Even if you don't want the text or image to span the full width, you can usually increase the margins on one side. If you can add larger margins instead of spacer banners, layout design is easier to control.