​How do I “find” my story?

I’ve been struggling lately with what kind of story I want to make. I’ve made many stories and characters throughout my life and have abandoned them all, but I want to finally make a full story, start-to-finish, and be proud of it.

The only problem is that I don’t know what kind of story I want. I make characters with vague concepts that I need to scrap because I don’t like the plot they were made for, and I can’t wrangle them into the new concept since they were dependent on the first.

I have themes I want to incorporate, but I end up not knowing if I can manage them because they’d fit better in a fantasy versus a grounded setting; do I want to make a fantasy with a power system, or do I want a psychological thriller? Why not both? Can I manage that? Do I want a small-town mystery, or a large-scale political struggle?

Long rant cut short, how do I “find” my story? How do I know which characters I want to bring to life, and how can I tell which genre and which plot is the one I want to dedicate the most time and effort to? How can I make something that I know I’ll look back on and think “Yes, this is who I am,” and know that it was meant to be the story I’m supposed to tell?

Some of the greatest and biggest stories were written across multiple years. I don’t expect to craft a masterpiece within a month — I also know that it’s probably better to write smaller stories while I build up this grand tale in the background. I just don’t know when that grand tale will “click” in my heart.

Kind of an odd question, but thanks anyway for any advice or response.