Anything you do that does not get you closer to the question of “will someone pay for this” is not what you should be currently focused on.
Your initial focus should be on idea validation. Figure out if people want your product. Figure out if it solves their business problem. And most importantly - figure out if they are willing to pay enough to sustain your business.
If your looking to make your product look more unique without spending a lot of time designing - use a design template. I talk about how you can quickly iterate with a design template here.
Remember, most startups end up failing. If you spend months on design out of the gate - you are statistically wasting your time.