Bringing a product to market requires thousands of hours of commitment and hundreds of thousands of dollars to make it happen.
Sure a designer can give your idea the once over and determine if it is “feasible”, but that cursory look is pretty much meaningless in the overall process.
That is why you need the business plan to determine the resources you need. Determine the steps and go/no go points, be prepared. From your OP, it sounds like you are doing this by the seat of your pants, being reactionary. “This is neat, now I need money.” I don’t know if that is your next step because you have not shared a plan. Anyone jumping on without a plan in my opinion is a fool ready to waste a lot of time and money.
And as you got charged by your lawyer for your patent in the $200-$350/hour range, expect to pay a designer in the $125-$200/hour range.