Core decks vs extensive reading

Have you actually tried reading any VNs yet? Depending on where you are, 1-2 hours of reading might not actually get you all that far.

Anyway, SRS is the way to go. You won't remember the vast vast majority of the new words you encounter without it, and your vocabulary is probably small enough that you can't just not care about that, because those words will keep showing up but not with enough frequency for you to actually recall them (or you'll see them five times in a short span and then not see it again for six months).

Do try and find some automated process for doing it though. There are a lot of tools out there for processing things into Anki cards.