Have there been any planned updates in this area? FWIW, I think I have stumbled into a brilliant solution for this implemented by an Obsidian plugin that could translate very well into Supernotes.
You can check out the details in GitHub - darlal/obsidian-switcher-plus: Enhanced Quick Switcher plugin for Obsidian.md, but fundamentally, it uses a search modal with simple prefixes to navigate around a file (in SN this would be a card of course).
For example popping a modal with a ^ character immediately shows the linked cards. This would be the actual back-linked and front-linked cards as well as parent/child cards. You could also customize this syntax further, if you wanted to target specific relationships, say only “child” cards. This way, while editing/viewing a card the user has immediate keyboard based search window into a specific relation set of cards.
The biggest draw is that not only can you traverse the current card, but you can actually traverse the cards you find in the search modal. So you can look through linked cards, find one and then look through its linked cards, all in a single search modal without any clicks.
I think this would be a huge upgrade to the current approach that I find quite limiting in SN.