[0]https://acoup.blog/2020/07/24/collections-bread-how-did-they...
- tens of millions died due to starvation from central planning issues (variously causing: a plague of locusts; Mao wanting to save face so refused foreign aid and maintained being a net exporter of food while people were starving; diverting people away from agriculture to metal production to meet the five year plan)
- millions died from government beatings/torturings to death, and suicide due to hopelessness and government destruction of cultural traditions in the name of centrally planned progress
Now one might say that there may have been even more harmful centrally planned economies, i.e. the USSR and Nazi Germany, but at best any of the candidates is competing to be only the third worst disaster in the history of the world.
Also I find it curious that among the possible causes you forgot to mention World War 2. What would you say if someone omitted that when explaining fifties in Europe?
If you think WW2 was a major contributor to the Great Leap Forward deaths then just explain, rather than making oblique comments about how it's strange I didn't mention the thing that you're thinking of (but not mentioning).
Exactly how bad it will get remains to be seen. But the causes of famine are generally political and in terms of total body counts the worst ones are basically "big country X really screws up" (e.g. China and the Soviet Union in the 20th century) and/or wars and I don't think we have any guarantee that those things won't happen again.