There’s no limit. You could write a single chapter of 500 words and call that a full story if you can mage to tell one in that space lol. I’m at 22K words on my sci-fi novella, which I’m close to wrapping up, so it’ll probably end at around 30K or so. My fantasy Novel however, I really want to see if I can reach at least 60K words, although I read somewhere the minimum for fantasy should be 80K, but you gotta start somewhere lol