As for your second request, I think it is a great idea and may be the solution that helps with an issue I have struggled with for a long time. For embedded content, there is always a scrollbar if the content is lengthy. I wish there weren’t and that it was embedded in its entirety.
Perhaps there could be an option to trigger a folded state of embedded content once it exceeds that length where currently a scrollbar is created. As a solution to my issue and perhaps yours as well, this “collapse” or unfold would simply expand the entire content of the embed. I am not against the headings within the embedded content being foldable on their own like in their source note, but see the main collapse functionality as being a button or arrow at the bottom and perhaps also the top of the embedded content with an appearance noticeably different than regular folding arrows.