All of the above is sound advice.
It sounds like you have some working prototypes. One thing you could try to do is find a designer in your area who you could buy coffee and just chat with to better understand what the process might be like.
Also, think about what you want to do with the idea. For example, Nike did not invent the Air Technology, they bought it from an inventor who tried to sell it to other, more established (at the time) footwear companies. You might not want to go through the effort to replicate what an existing footwear company has built (design, development, sales, logistics, distribution, warehousing…) or on the other hand, maybe you do want to own it from cradle to grave.
Also, there are some footwear development houses that can be helpful. I think there was one in Portland called Shoe Dogs for awhile.