Wondering if potential angel investors hesitate because: idea, market size, you. A dedicated founder in a good market is often fundable.
A little bit of everything. No one knows if this will work because I don't have customers, and it looks like a feature and I can't explain that it will be more than this single product, investors are getting lost. It's impossible to make this startup without a weird path. It's going to be an API in the end, but at the same time I have to show what products are possible to make with it, most think this API is not need…
What the hell is wrong with you?
You have no customers and an idea you can't explain. What makes you think you can build this unexplainable cusomerless thing into a business, let alone LITERALLY mortgage your future for it?
As others have said: No. Under no circumstances should you sell your house to fund... whatever this is. Bootstrap it nights and weekends if you feel passionate, maybe go find a co-founder if you can explain it coherently.