>>996143
It's kinda easy. Thanos uses a Macguffin, Darkseid doesn't. Darkseid has his laser, an opportunity for cool visuals (oh wait… a current DC movie and cool visuals/ CGI… never).
Also, he talks much about how evil, powerful and diabolic he is.
Thanos on the other hand is calm, calculated and thinks of himself as the hero.
Theoretically, Apocalypse is also like Thanos and Darkseid, but in the movie he's unique, too. Bland though. Just make their behaviour and character unique, that's all.
Oh wait, DC can't make anything not generic.