Having just watched "Ghostbusters Afterlife" again tonight (since it's been a while), I agree that there needs to be a presence within the park again. You can feed off nostalgia while also giving something fresh/new.
A dark ride would be fun, but a special effects driven "attraction show" like before would be just as good. I'd say bring back the hilariously entertaining street show (featuring Beetlejuice), but use an updated playlist for his possession songs (KPOP!!)