That's not a creative slump, that's a lack of planning and dedication. Here's a question you should ask before creating anything: what do I want the viewer to get out of this piece?Given i can't get these stories past the 39,000 word mark I'd like to try something else, but nothing seems to be working
Do you want to make them sad? Do you want to make them angry? Do you want to pose an ethical question? Do you want them to laugh at a magical world of absurdity? Do you want them to watch two lovers who were torn apart get back together in the end? Do you want to tell the story of someone stuck on an island? Do you want to tell the story of a regency era's young girl's adolescence? It doesn't really matter what you want them to get, but everything else about a story is malleable and subject to whimsy--plot, characters, everything. If you don't set in with a clear goal, you'll just kind of float around with no direction, whereas if you have a goal to work toward everything else is about moving forward towards it. I've heard that every story needs an overarching theme, but I don't think you need to plan it out so specifically like that, so much as you need to go in what an idea of what you want to get out of it... if that makes sense. Overthinking is just as bad as underthinking a story.
On a more personal note, I always make my characters first, then decide on the climax (NOT the ending). I do this for two reasons: character creation is my favorite part of writing and, by knowing what the climax is, I can build events leading up to it based on how I know my characters would act in a situation (since I made them beforehand). This way, there is always some kind of forward motion I know can be made, since I'm going somewhere specific, and the ending should just be the logical events after the climax.
Your initial statement:
Sounds incredibly dull from the start. Maybe your protagonist is bland and has no real motivation, and thus isn't moving the story forward. I find the main character is often the most difficult character to create. I've seen a lot of stories with this kind of setup, where the author spends a lot of time creating an alternate world, but virtually none on the protagonist. Some try to defend it by saying the main character is a self-insert for the reader, but the main character should have a goal to strive for and a definable personality imo. I don't relate to nothing, but I can understand someone who is different from me, at least, even if they act in ways I never would.Lately I'm finding the only way story I can do is with the protagonist getting fired from their job and then discovering a magical realm down the block.
Actually, why not just have the story start in the magical world? I often find that "normal person finds their way into magical/special world" to be very... uh... they take me out of the experience, not draw me into it. But a story that just takes place in a magical world could be interesting just by virtue of being different from real life, and I'd have to suspend my disbelief less. If there isn't a very good, specific reason for why the story starts in the "real" world, I'd say skip that part. The recent popularity of isekai stories in Japan may also result in some feelings of over-exposure with the concept.
Also, don't worry about word count. Make a complete story. Make it as short or as long as you like, but make it complete. It's like writing an essay in high school--so many don't have anything to say, but pad the word count with bullshit to fulfill a requirement. No one wants to read that. I'd rather read a shorter story that told itself than a longer one that wasted my time.