My thoughts...
I didn't like this movie. That said, I think I "get it". My guess is the director was trying to comment on the idea of "white privilege" and entitlement. The older brother and the mother represent the West and how many of their ilk seek out countries like Thailand to exploit their corrupt governments by doing things like engaging in sex with minors (which obviously is sickening). The character Juilen, I guess could be the manifestation of "white guilt". My guess is that the film tried to invert stereotypes of the Other and the so called "dragon lady". The film felt very surreal. Like a dream. Almost like an out-of-body experience in a way.
The thing I didn't like was the fact that there was little understanding of what the Thai characters were saying until like 20 minutes into the film. I get that it was for suspense but it bothered me.
Also, can anyone explain the dedication Jodorowsky? I know the director is a fan of his work and they might be in dialogue with one another but I'm interested if there was an actual discussion between the two of them about making something like this.