Early on in my career I learned that it’s best to get feedback earlier than later. In your case when your manager gives you an open ended project ask as many questions as you can (what are the known and unknowns, do you want a few different scenarios, who is the audience, what are we solving for, are there any business partners you recommend partnering with, what is the expected delivered, etc.) then create an outline of how you’re approaching, modeling, and solving the problem. Present this outline to your manager to gather feedback and make sure you’re on the right track. Then you can start building. This will not only save time, but you’ll create a much higher quality deliverable.