I would pay a lot to launch what I have. Who has captured this market?
I don't really need a technical lead...they would have no understanding of what I made or why it would be useful.
I've tested it in the field and I know it works for exactly what I want it to do.
How much/ What exactly are you willing to pay?
And what exactly do you want from the person, do you want them to build their app?
So what do you need then? Your posts are a bit confusing. You asked for solo senior developers but then you say you need help with pricing and trademarks and also say you don't need a technical lead.
I would suggest you organize your thoughts and write down the list of what you think you need and then either pay for a consult with a senior developer or chat with a trusted technical person.
From your posts, it sounds like you need more than one role and/or the services of an agency. If money is the issue and you think you have a good idea, then I suggest you seek funding.