So I began to reread some of my comic books and started with Superman: Braniac. The story has it that Braniac captured Kandor in a bottle and fired a solar-aggressor at Rao which ignited it and it blew up Krypton, not including Argo city.
Then, continuing the story line, Kal-El goes to New Krypton after the incidents in Superman: New Krypton.
In Superman: World of New Krypton, there is a flashback in which Jor-El explains that the planet was going to explode and it briefly shows the planet exploding with Kal-El's rocket flying away. Rao is still intact.
So I'm wondering, did I get something wrong? I never noticed this discrepancy before. Perhaps I missed something. But also, keep in mind that I stopped reading at this fact to look for some answers. If the discrepancies are explained later, please kindly let me know with a spoiler warning. If not, can anyone explain to me exactly what destroyed Krypton in this arc? A solar-aggressor which destroyed Rao which destroyed Krypton, or Jor-El's theory in which the planet would explode?