I would say :obama-socialism:
Some might argue its Bush Jr. but Obama destroyed so many nations that his death toll arguably surpasses Dubya's once you include the Ukraine war. One top of that, the Iraq war sparked the largest protests since Vietnam, while Obama's destruction of Syria, Libya, Ukraine, Venezuela, etc. went largely unnoticed by the public. Obama also single handedly annihilated all progress made by Black and Hispanic communities when he bailed out billionaires and bankers. What's worse is that the psychopath is largely popular, worldwide, and libs think that his biggest scandal was wearing a tan suit.
I mean depends on how far back you consider "recent" but Reagan is always a strong contender.
I think Obama is a fine pick though, for all the reasons you listed. In general libs tend to ignore the atrocities of their own, so Democrat presidents end up feeling a little more unbearable due to that lack of background resistance (or, you know, "resistance").
This is why I vote Obama. It's impossible to truly quantify the ghoulishness of each president without significant scrutiny but Dems and especially Obama get glorified by so-called progressives that I despise them more based on vibes.