The whole no computers thing in Dune never made any sense. The only difference between a computer and an industrial controller is scale, not kind. We had wood computers in the 19th century. Some of them are still operating.

Ok lets talk about sewage. To turn human feces into dirt we use stages, to move from stage to stage we use screw conveyors. Without computers how are you going to regulate the speed of it? When to run them? Deal with clogs? Report motor problems?

Nothing would work beyond about the 1840s. And yet they act like it does. Which brings me to my fantheory about Dune: Just assume everything is told by inbred religious royality morons cosplaying and it all makes sense. Why do they fight with swords? Why cant they fold space without spice and yet clearly could in the past? Why do they think the Bene witches have powers? Because they are religious royality morons cosplaying.