who i am is exactly the same as who you are

Firstly: the Missionaria Protectiva seeded the Panoplia Propheticus on various worlds as a general tool for Bene Gesserit interests. It was there to be exploited by any Bene Gesserit who needed to take advantage of a planet’s culture and gain power there for any reason. It was independent from the Kwizatz Haderach project and was probably exploited many times throughout the history of the galaxy. The Lisan al-Gaib is not the Kwizatz Haderach and could have been any old Bene Gesserit who found herself on Arrakis.

Secondly: the messiah legend is false, but Paul is not a false messiah. Because he happens to also be the Kwizatz Haderach, he is able to deliver on the false promises of the Panoplia Propheticus and he chooses to do so. I know people claim that Dune is ambiguous about whether or not his visions are “real” but I find that really unconvincing. He’s able to use his prophetic memories to navigate perfectly after he is blinded. They are materially real even if they are philosophically dubious.

Thirdly: Frank Herbert may have sought to critique the danger of heroes, but the reason Paul is portrayed as “bad” for the Fremen is because he literally does liberate them. He fully delivers on the messiah thing, ending their oppression and elevating them to power and status throughout this galaxy. Why is this bad? Well, because they are spiritually corrupted by material comfort, of course! Access to abundant water leads to their ~cultural degeneracy~ and they lose the noble savage status of their pre-Muad’Dib ways. They’re too sexy and relaxed and hydrated and this is a tragedy because they no longer expel their disabled into the desert to die and are thus racially diminished by their liberation.