I think there is no simple way to do this. You can try to override ModelAdmin class but this is not a "simple" way.
From this answer it seems like it is possible to use ModelAdmin. Formfield_overrides to override the ManyToManyField to use CheckBoxSelectMultiple.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.