The author of the post linked above talks about Terry Pratchett as a good, high-profile example. The problem? Of all the people you could point to, Pratchett is the least "stealth" about his worldbuilding for anyone who writes standalone fantasy novels. Why? Because none of his novels are de facto standalones when they have the enormous Discworld title printed on the cover. You know right from the start that this book is in Discworld. No stealth about it. There's no secret moment where you can go "oh, yeah, that's another part of Discworld and I totally didn't know." His books are clearly labeled as part of the same world.
The rest of the examples seem to suffer from the same problem. Shouldn't it be obvious that if the worlds have the same names, then they are the same worlds, and thus no longer being sneaky about it? And if the names aren't obvious, how exactly does that make the worldbuilding stealthy? The author is still building a world, and very obviously so, populated with characters and cultures. The only thing that seems to support the term is that some years down the line, books you didn't think were linked suddenly are. But that's not a new thing in fantasy. That's been happening for standalone novels and series for decades (maybe even the better part of the last 100 years). Half the time it's not even a stealth technique; that would imply intention from the start of a particular set of independent novels.
Readers like to have this fantasy that all writers have a grand plan in their heads, but the truth of the matter is that most writers don't (not in the sense that we're talking about here). Some writers write a standalone book, find out it worked out well, and are prompted by their publisher to write another one, maybe as a sequel or as a new addition to the world, or decide to write another one for the thrill of it. Some writers have a little bit of the plan in mind, but didn't expect, twenty years down the line, that they'd be writing the one book that put all the pieces together. Few writers have that enormous plan already set up (though some undoubtedly do).
So, I reiterate: what exactly is stealth about all of this?