SW certainly ramps up in difficulty based on the setting. Of the ones I've played, here's the ranking in complexity (from Number 1 - most complex to Number 3 - least complex).
Well, Rifts was absolutely going to have a lot of moving parts, and depending on how they expressed the Pathfinder approach I can see it there.
Note of these three, two were situations where they were porting over properly representing other games that I consider significantly more complex than native SW, however; its probably not surprising that upped the practical complexity to some degree. Even though they has some things to keep track of, I didn't find either my XCOM or Broken Earth games nearly as complex to run as I suspect those would be (they both ended prematurely, but that for reasons that were largely non-systemic).