I feel like a lot of zombie fiction where characters know what zombies are and the dangerous of getting bitten end up being semi-satirical comedies. Movies and shows where the idea of zombies didn’t previously exist seem to be a bit more serious from what I’ve experienced. I don’t know if it’s the aura of suspense and mystery or because it leads to more pandemonium.
The issue these days is that everyone and their grandma knows the basic rules of zombies, so if the characters within the story are completely clueless, the audience is going to impulsively think the characters are idiots.
I think the trick to creating good zombie fiction these days relies on subverting the existing tropes and knowledge. If the zombies you’re writing are sufficiently different from other examples in the genre, it won’t matter if the characters have knowledge of tropes or not. If you have a scene where a zombie gets up after having their head chopped off, then it doesn’t matter if characters in the story “know” that chopping off the head kills the zombie. You’re no longer playing by those rules, and tension/suspense is returned to the story.