"Has any previous president failed his big test as thoroughly as Trump has these past few months?"
James Buchanann, James Madison, Woodrow Wilson (to be fair he'd had a stroke and his wife was running the show from their bedroom). Herbert Hoover. These are all in the running, a final accounting can't happen until Trump is out of office and we can examine the whole thing.
I do think that future historians will study this presidency to understand how not to do things.