Dating a super-smart and successful guy for past several months. He literally remembers nothing about me. Doesn't remember that I don't drink alcohol (even though we joke about it often), doesn't remember that I'm a plant-based eater (again, we joke about it often). I've spoken about my childhood to him and then once in awhile he's like - wait, weren't you raised in X situation? I'm like um, these are fundamental things. He's just not into me or he's a moron? What gives? 45 years old!

Maybe he’s dating other people too? Either way you deserve a lot better so move on
Definitely this. He is having a hard time keeping track. And it also shows it's not important enough to him to pay attention and make an effort to remember. When you are talking he is just going through the motions of listening but he doesn't really care. Move on.
"He literally remembers nothing about me." Why are you dating him?
He may be into you, but not enough to warrant spending (or rather, wasting) more time with him. These are basic things to be losing track of. Tell him it's been fun and then block him.
Those are basic things that I would expect anyone I knew to remember about me if we talked about it several times, especially someone I was dating. You deserve better.
Dating other people. Have you had the exclusive talk yet ?