You are correct, this is not currently possible. However it is something we would like to add, as it is definitely a nice flow (and one I personally would appreciate).
We are working on a wikilink system for Supernotes, as mentioned in this thread. The main hold-up with wikilinking to non-existing cards has been the issue with Supernotes where (unlike in other systems), we do not require note titles to be unique. Card IDs are therefore just randomly generated, as if they were a hash of the title (or something similar) you’d end up with lots of collisions.
This means if you link to the [[The Hobbit]] in one card, then link to it again in another, then create a “Hobbit” card, it is non-trivial for Supernotes to guarantee that all those pre-existing links will end up pointing to the same place. This is compounded by the collaborative nature of Supernotes, where you might create a card called “The Hobbit” and another user might create a card called “The Hobbit” and share it with you, so two [[The Hobbit]] wikilinks might not even be intended to point at the same card.
We have some ideas we’ve been toying with for a long time, but because this is a change that will fundamentally alter how people edit cards we want to make sure we get it right the first time, as it can be hard to “take back” depending on the implementation.
That said, if anyone has some clever ideas for how one might achieve this in Supernotes, please let us know. It is entirely possible we have overlooked a best-of-both-worlds solution!