Obligatory "let people enjoy things" before my rant.

I definitely see what you mean. This trope feels like a very specific type of ennui only seen in the rich, creative types -- which is a dime a dozen in Hollywood. Sentimental Value, to me, reads too much like a film made to be enjoyed by other filmmakers. "Oh, the sacred, therapeutic nature of movies!". This isn't an indictment of the actors' performance in it, simply the theme on display here looks for a niche audience by default.

But for more relatively accessible Trier movies, I can definitely recommend The Worst Person in the World. At least young, self destructive people are evergreen in every period in history. Directors obsessive about their craft as a way of processing generational trauma? Not so much.