It works as a stand-alone show and you don’t need to have watched Dune and Dune 2, but it does help provide some context if you did. Some of the stuff in the show aren’t even referenced in the movies (yet, only in the books), so watching them won’t really help either.

As a Dune fan, I found it just alright/mid. Not great, but not too bad either. I agree with the other comment that it’s better binged, else it will feel dragging. Hopefully they improve for the next season.