If you use GenAI for any sort of brainstorming (and I suggest caution here), have it make you large lists of ideas that you can choose from.
If you use GenAI to create a lot of ideas, it can help get some ideas going while still allowing you to think through the suggestions and make the best choices. Whereas, if you have GenAI generate just one idea and stick with it, that idea might 1) not work well for the assignment, and 2) not be an idea that you feel like you can write about. If you don't understand the idea enough to write about it, you'll be more likely to want AI to help you with the next step and the next.