New user here 
Really enjoying your implementation of hierarchy so far. It was actually one of the first things I came to search for, as nested cards quickly grew under a parent.
An automated table of contents on parent cards, triggered by syntax like ^TOC or some other short snippet, would be fantastic.
In Obsidian, I used to do something similar (but in reverse) with Dataview, creating a tree of backlinks. I’d really like to flip this in Supernotes and have contents links displayed on parent cards. Even better if there were an option to toggle parent cards (with children and no content) into TOC cards by default, or to toggle any card into a TOC (and back).