How do you start designing a solution without understanding the requirements?
How do you start building the marketing campaign without knowing your audience?
How do you starting testing for performance when you don’t know the baseline to start from?
You definitely can start doing all these things, no one is stopping you.
But you will miss the mark simply because you and your team didn’t understand the problem when they started working on it.
And without knowing what problem you are going to solve, you will always get it wrong.