You’re not a lost cause, learning any kind of new mindset takes time.

I think that what you’re doing with writing stories based off those you liked when you were younger is a great place to start learning the components for a story, and figuring out how to work with them.

Something that helped me learn how to write creatively was trying to imagine what a story’s sequel would look like if it didn’t already have one. Then I’d try to continue the story with the same characters in new circumstances, imagining how they might react.

Then maybe once you’ve had some time with that, you could try to pick a general takeaway theme/motif and write a story about that with your own characters and universe and everything.

Also, don’t critique yourself too hard if you hit a wall. There’s ALWAYS something new to learn that you’re not going to be aware of the first time around. :)