is it ever mentioned in canon how karkat's ectobiology is more complicated than john's? is it not just that the beta trolls are actual clones of the alpha trolls?

The beta trolls are not clones of the alpha trolls. Karkat created 24 trolls during his ectobiology. Trolls are usually conceived when the Mother Grub combines adult troll reproductive liquids and then lays many eggs all at once. Karkat may have had to do a similar process but with paradox slime for 24 people.