I agree Heinlein wrote one-dimensional characters; the male heroes were idealised versions of himself and the women were objects of wish-fulfillment.

Pohl wrote pretty well in my opinion. The psycho-therapeutic aspect of Gateway is brilliant for the sci fi of that era.

Plenty of sci fi authors wrote characters comparably with PKD, such as Zelazny, Le Guin, and Bester.

Le Guin is a great author but I struggle to engage with her characters. Brian Aldiss I think does better? And Vinge? This is sticking to the classic era. The genre has changed and there are too many more recent excellent SF writers of character to do justice to in a post

Maybe a subjective thing then, as I remember enjoying the joint character development of e.g. Ai and Estraven in Left Hand of Darkness.