a sequence of floating islands at max height area. it generates after the cultist is dead. it appears as the void and has its own enemies. this would be hard to program so its probably never gonna exist.
Actually there are some modders which are even better at coding to the point that they can fix bugs which were present in the code before the devs even knew they existed. Plus they’ve actually also been able to make straight up improved versions of existing content with better code too. The best example is that they’ve actually been able to add full on dimensions akin to the nether from minecraft into the game, which is something the developers couldn’t do.
Also, what you’re proposing feels like post worldgen structure generation which is already something modders have been doing for years.