Can the Gutenberg editor be toggled closed?

You can’t move metaboxes/panels above the content area, they don’t logically sit in the same place/depth.

Unlike the classic editor where everything is listed vertically by HTML markup, that’s not how the block editors UI was designed. Instead there’s a canvas with a block-list component, and a frame that contains the top toolbar, the sidebar, and optionally a drawer/area for metaboxes.

If you want to place controls and options above the content, they will need to be built as blocks. Otherwise what you want doesn’t fit into the new paradigm. Perhaps your post type has a template defined on register that locks it to a custom block you built, and allows child blocks that make up your content? Or perhaps you can make use of ACF blocks