I agree with you. The production design for Joker didn’t really stick out to me, then again neither did hair and makeup or costuming or sound. Creating 80s New York City isn’t necessarily a marvel considering every movie has to at least somewhat effectively create the setting that it’s in. I’d even make the argument that Joker didn’t recreate 80s Manhattan as much as it evoked the feeling of it by creating a generic 80s metropolis whereas a Once Upon a Time in Hollywood, Irishman, 1917 and JoJo Rabbit actually recreated real places.
All of the movies nominated deserve recognition way more (still haven’t seen 1917, it just opened this weekend). IMO, Parasite should win, but it will likely go to Once Upon a Time in Hollywood due to the Hollywood aspect. So many academy voters will be able to see the Hollywood that they remember in the film. But Parasite doesn’t work with out the Production Design. Both the main two settings that they have help tell the story in ways that you couldn’t without it. For the other four, the production design helps with immersion while Parasite’s moves the story. That combined with the editing and cinematography, I found myself not reading the subtitles and still understanding the story.