Bloodborne dun fucked it up in the story department as far as I am concerned: I have not read the aforementioned novels, but I should not need to: Demon's Souls and Dark Souls presented an engaging story without any prior knowledge of anything, Bloodborne fails to do so for me.
I have finished the game, but doubt that I'll be returning to it upon - if, I ever read those works.
See I am the opposite. I invested heavily into beaying and learning the mythos surrounding Bloodborne. Hell I beat the game 7 times connecting the dots. However, I have NEVER read any of the fiction novels that inspired it.
I will say this though, I was so captivated by the depth of the plot, that I did do a little research towards lovecraft after the fact. I did not need to do that to understand everything, but it did deepen my overall understanding of it all.