IMO, if there was hard evidence in the documents seized, they likely would have already been leaked.
This is where I am with pretty much anything the FBI (or ATF or DOJ, etc.) do and say as of now, for anything, not just Trump. If they had irrefutable evidence, they would have presented it instead of playing redaction games or, "We can't release "X" concrete evidence due to security, judicial process, or any other lame excuse we can come up with, but here's oodles of circumstantial stuff that just causes more questions."
I'm getting tired of, "We can't release the primary evidence, but here's some unrelated stuff to rile everybody up."