Yes, TLJ is postmodern. But does that mean it’s bad? I actually felt like the postmodern attitude of TLJ was a nice change of pace, especially after the boring corporate nostalgia bait that was TFA.
I thought the postmodern aspects of TLJ were interesting departure, but it certainly was jarring on first viewing. No other Star Wars movie is really self-analytical like TLJ, so if you’re not interested in that I can see not liking the movie very much.
Again, my problem with TLJ is that it calls into question the good and evil paradigm that has been perpetuated throughout all the SW movies which is cool (“Good guys. Bad guys. Just made up words.”), but at the end of the movie we’re just back to good guys vs. bad guys.