ANSWER:

These are two separate supplications! Going to paradise doesn’t mean you won’t be tormented in your grave!

You should recite both.

Sheikh, whoever recites ayatul kursi after every obligatory prayer the only thing that stand between him and paradise is death, so do we need to recite surah mulk before going to bed because we will be going to paradise INSHALLAH, that means we won’t be tormented in grave.