I'm afraid it doesn't work this way. Developers generally don't have a shortage of ideas or problems to solve. People suggest ideas all the times. Usually they have no idea if it's super difficult to implement or already a solved problem. And if people do the programming in their spare time: They need to be involved or personally motivated somehow. So you need to find people who also want it.

My advice is: Find out where those people mingle, who would have some personal motivation or involvement with your topic of interest. That is the right place to ask. My personal oppinion: Feel free to also spam the internet and places like this with your idea. I'm a proponent of "Don't ask to ask, just ask". People can always not read your post or can guide you into some direction. It's probably okay if you do it a few times too many. Just don't ask in a hundred places at once and then don't read the replies. If you're better than that, you're fine.