Haunted Mansion is my pick.
It is the pinnacle of what makes Disney parks great. It transports you to a place that's familiar but one you'll never actually be able to visit. It's full of fantastic sets & animatronics. There's even a super iconic song to go with it. The ride is still incredibly impressive IMO, even after its existed for decades.
Kilimanjaro Safaris, Everest, Big Thunder & Muppets 3D are my follow ups. I almost want to say Rise too, but I wouldn't say no to a retheme to the Original Trilogy or Mandalorian.