Adaptations of big, complex books tend to start slow — and that’s usually because there’s just so much to explain. It was true of Game of Thrones and The Rings of Power, and it was especially true of Foundation on Apple TV Plus, which took Isaac Asimov’s novels and turned them into prestige television. With unusual concepts like psychohistory (a kind of math that can predict the future) and a genetic dynasty (a never-ending line of clone emperors who rule the galaxy), the first few…