To view design only as the latter part of this process—the rendering of the solution—is incredibly shortsighted, and detrimental to the overall value design can bring to the product, service, or a business.
Sometimes the problems we start out with are a given because the stakeholders are already aware of them. A lot of times though, these problems need to be discovered, and designers need to learn about them first so they can be sure they are the right problems to solve.
Designers can solve problems only once they are comfortable with them. They do this by using whichever tools necessary to equip themselves with information, or through previous experience.
Solving the problem is actually done in the learning part of the process, not in the execution part which is simply the rendering of the output. You learn about the problem, gain the knowledge about it, decide how to solve it, and only then solve it.
The rendering of the solution is the last, and least complicated part of the design process. It's purely executive.
If you are not allowing designers to learn about the problem space and set them up to guess their way to a solution, this may be the reason you have a problem with designers, or getting value from design as a business asset.
Image created with ideogram.ai