The thing that keeps trump out of jail is the plausible deniability that he was involved or at fault. There’s probably enough evidence against him, but not enough that even corrupt judges can’t look the other way. And he can just appeal to he gets a judge corrupt enough. So investigators have to handle this like any other criminal organization by starting at the little guys and making deals with them to turn on the person above them, then get them to turn in the people pulling their strings, and on and on until you can get enough people willing to testify in court that trump was in fact part of it. I say part because I don’t credit him to be smart enough to be at the top of this. He’s somebody’s useful idiot.