I know this question might sound weird. But before when I wrote fiction stories I was writing chapter by chapter, even I did not know the end until the end, this gave me so much excitement to write and finish my stories. Now been trying to write fiction with story based on my life story experiences. It takes the fun to plan the whole story in my head. How to stop and get back to the way that I used to write?
some stories benefit from outlines. some dont. I'm the type of writer that writes by discovery. which is, I just write and however the story turns out, it turns out. BUT, I have some stories where I cant do that. I've made outlines for those so that I can see the path that I want to take, and how to get to the ending. Its just how the whole writing process is. If this is how your mind wants to organize a complex plot, then i'd go with it. why want to stop the creativity?
I generally have a beginning and an idea of where it needs to end. In between, I, too, let the story happen as it happens. I'll give it a gentle nudge if it starts looking like I won't make the planned ending, unless the story comes up with a better ending. One thing to consider when planning everything out is the chance of story fatigue. By the time you're starting to reach the end you might be done with the story already and write it just to get it done. I don't plan, but I've read many an interview with bands and videogame developers and the good ones say planning is fine, just don't execute in order.
There are a lot of writing questions people ask where they go "How do I do X?" And my gut response is "By doing it". If you want to go back to the way you use to write, you should go back to it. Or rather, what's stopping you? You use to go chapter by chapter... why aren't you doing that anymore? Write however you want, just write.