If you had product-market fit, you would be able to finance from your customers. The fact that you say that you need additional development means that you do not have product-market fit. Realistically, you only know that you have product-market fit when you have active users; if your validation point is some interviews, but no usage, then you don't have it yet.
It's important to understand where you are, because being at actual product-market fit means that getting funding for a couple people for 12 months is pretty trivial, provided you can defend a TAM of $10M or more (based upon your actual usage).
If you're actually pre-usage, then you're asking for seed funding for an idea, either financially or through sweat equity. The chance that you get someone technical to commit to no income for 6 months is incredibly low. Most software developers (and UX designers and PMs) need a monthly paycheck, and the ones that don't probably aren't going to work for you; the demand is so huge.
If I were in your situation, I would go pre-sell my product to one or more potential customers as custom software development that is heavily discounted to them. Almost every success story I know that started where you are was done this way. Hoping and begging for free labor from some of the most heavily-recruited and highly-paid professionals in the world today is not a great strategy.