I think you read a lot of books that are post-2000. IMO the original 4 or 5 books imply strongly that it’s man v man, not man v machine

It's left fairly ambiguous by Frank Herbert's books. The Jihad is implied to have taken place over ten thousand years before the beginning of Dune - it's ancient history to everyone involved*, so it's only natural that the details are a little hazy.

*: except Leto II, and he doesn't say much about it