I've been working 15+ years as a UX developer, with varying results. From my experience, the best way to get developers and designers to work well together is to have frequent short demos/reviews (ideally weekly). That has helped solve random problems like:
1. This user flow does not match backend reality, let me explain why.
2. How does this screen design handle XYZ usage?
3. I cannot export this asset from figma, please share.
4. Would you mind verifying that the fonts/colors/spacing look okay?
5. Are you sure about not reusing an existing icon from our library?
6. How should we handle error and loading states?
7. How important is this design feature? It'll take me a while to build it.
8. Did you expect this desktop layout to be full width or 1600px?
9. Can you give me an overview of what changed since the last design version?
10. This is how I implemented the design. Is that correct?
Highly recommend Brian's Tacklebox program. It helped me create a framework for validating my product idea, while gaining the skills (and confidence) for running customer interviews, landing page tests, mapping markets, etc.
Obviously, you still need to put in the work to reach out to potential users. But the program helps you approach it in a structured format.
I've noticed strong feelings of obsession towards an idea/goal, particularly when it's not achievable.