It’s mostly going to be graphical assets. Especially in a game like this which doesn’t have much else going on, and is constrained in terms of what else it can do because the base game ran on PS4.
Even on PC most of your RAM is just being used as extra cache for graphical assets. Very wasteful tbh, but it is what it is.
I’d guess VRAM at 75% of console RAM to be a safer bet. So 6GB last gen, 12GB this gen. Maybe more if you’re pushing higher resolutions, but most PC gamers aren’t even at 4K, let alone going beyond it.