The simple answer is: good developers get paid.

You have a few options that each come with different risks.

1. Find a development agency looking for equity projects. There are more out there than you would expect but be prepared to show them all the details. They are going to want to see that you've done ALL your homework.

2. Find a freelancer looking for passion project. This is hard. Really hard. Try places live Reddit to post what you're looking for with as many details as you can share.

3. Create a "simple-er" MVP. Can up just design a mockup and sell that to investors or customers first? Can you find a way to do it without coding?

People will see value in a lot of ideas but the more you can show them that you've put time into the idea and have hard plans for success, the better the likelihood of finding someone for your project.

Hope that helps!