I do think Garland made a massive mistake. Nixon resigned; Trump did not. Nixon largely disappeared, as most former Presidents do during their successor's term. Trump was still communicating crimes and clearly intended more.

I'm drawing a kind of fine and possibly meaningless distinction here. I think Ford made the best decision he could at the time. Garland had the benefit of hindsight: he saw the way the corruption had become far deeper than the President himself. Garland should have known better.