Could’ve been a couple of ‘somethings’ - plus the angle and location would not necessarily require it to be as big as something hitting closer to the equator.
The only know somethings that hit the Earth and caused massive climate change were comet debris 12800 years ago which incinerated all life on the North American continent bringing on the Younger Dryas Age - the coldest period in ‘recent history’. Prior to that, nothing other than the Sun’s output striking Earth caused climate change.