I think you are factually wrong. The circumstantial evidence here that there was a quid pro quo intent by Trump is very, very strong. The timing alone screams it. No reasonable alternative explanation has been given as to why it was tied up. If there was one, it would have been tendered by now.
If this were a legal case, which it is not but to use your analogy, based solely on what is known now, there is more than enough to go to a jury. And I think you have to admit that the actions of the administration also suggest strongly that such evidence exists, either by testimony or documentation, they know it exists, and the entire focus right now is keeping that from going public.
Note as well on this front that denials of such have come from two people: Trump and Giuliani. Neither of whom I think anyone in their right mind would trust to tell the truth on this issue. Trump has proven himself to be a liar about far, far less. And Giuliani is a loyal soldier and would knowingly lie about it, so his testimony on the subject is literally worthless.