This is definitely something we would like to improve.
One problem you have touched on is that any card can have multiple parents, without necessarily being in an actual hierarchal structure. On other platforms, which only allow for a single parent at a particular level, it is trivial to trace “breadcrumbs” back to a “root” card. However on Supernotes your breadcrumbs can be a graph, which can be hard to show in the UI without becoming a mess.
One idea we’ve been toying with is to show breadcrums as you drill down, so if you are in Layer 1 and then open Layer 2 from within L1, it will show L1 as a breadcrumb in front of the card button in the top left of the noteboard. So rather than being a comprehensive view of all parents all the way to the root, it is rather an ephemeral history of how you’ve been “drilling down”.
So that is where we are with our thinking at the moment. Thanks for starting the discussion on this, would love to hear more thoughts!