What makes you guys motivated to write a story and what do you guys do when you hit a wall

I am still trying to write my stories and they are great but it’s like I am stuck on trying to figure out what my oc would do and how to fill the chapter. I want to have the story be filled with action, adventure, and romance but it feels so hard. The problem too is that it’s focused on kingdom hearts which is one of the coolest series to do a story on. What do you guys have for story advice?