I read Archie comics as a kid as well, and as a kid, I never considered Jughead to be "asexual," I just thought he was just more interested in food.
At least through two episodes of the show, Jughead is pretty close to his comic character. He's shown no interest in romantic relationships at all, and mainly just wants to eat food. He's not even a main character, he's more of the narrator or Greek Chorus, providing exposition.
I'll admit, the whole Archie and Ms. Grundy thing is a bit odd and creepy, but the show is definitely straying from the source material. Reggie is Asian, Moose is secretly gay or at least bisexual, and Betty and Veronica are friends.
The show isn't going to set the world on fire, but I'm digging the Twin Peaks-esque vibe I'm getting from it.