his dads' books didn't give any strong warnings other than we may grow 'overdependent'.
the sentient evermind enslaving millions thing was his sons concept.
It's also worth noting that Frank Herbert doesn't seem to write his ethics against an absolutist framework. The use of nuclear weapons is considered commonplace, hereditary and boring in Dune's future, despite the historic protest against their development. Concepts like Jihad, strong leadership and faith are equally rewarded and punished in the fiction. Paul's leadership succeeds in freeing the Fremen, but it undermines his secular authority and creates an even more violent reprisal.
Suffice it to say that Frank Herbert understood nuance. He would probably understand that LLMs are not made in the likeness of a human mind any more than the C programming language is. Teaching computers to use language is not a step towards Dune's transgressions, and doesn't invoke any themes to me.
Why do you feel differently?