There usually is a lot of work when producing a new product. And only half of it is about the device.
I'm willing to give you some time, listen to what it is that you want to accomplish. And then hopefully point you in the right direction. If you don't want to release too many details publicly then you can message me instead.
First thing, the big picture. What is it you want to make? How many do you think you would need. What kind of time frame?
I have been designing electronics (my job) for 35 years. Mostly products marketed by the company I work for, but also custom products for other companies to market. The main purpose when designing for other companies is to provide contract manufacturing.