Its development is really interesting, in that it was more a proof of a scientific paper to start with. Anyway one of their tweets from September 2024 indicates they're working on a sequel, despite their publisher (Annapurna, owned by Megan Ellison, daughter of Larry Ellison) having had some issues around then.

they are working on a new game. Outer Wilds doesn't need a sequel, leave it be, its perfect as it is ::)