Death by a thousand cuts was a concept made famous on earth by movies and shows that used it to demonstrate how painful and brutal death could really be - also to build up a villain so that the main character looked cooler after defeating him.
For a normal human, it was definitely a painful way to die as they bled out from the numerous cuts on their body. For an immortal, it was just painful.
Diyor had not yet realized it, but he would never be able to kill Lex. Yes, his divine energy allowed him to create a miracle and harm Lex, but that kind of damage could never kill him even if he just stood there and let the attacks fall.
Yet that's not what Lex did. No, he resisted as if Diyor had gained a decisive advantage, keeping Diyor dedicated to attacking him. His purpose was simple, really. He was using this fight to test out his theories and expand his understanding of the universe.
