The dialogue and character interactions in this are very bizarre.

I agree and I think it transcended his work as a director, look at how he treated Shelley Duvall outside of the technical nature of his directorial duties, she wasn’t a person to him, just a means to end.
If always makes me sick when I think about what he did to her, and how how no one stepped in to defend or support her, or maybe they didn’t know, but that seems unlikely.

From 2001 and beyond his actors are stilted and robotic. In his early movies they act more natural.