After reading your review, I immediately looked this film up and found it streaming for free (legally) on YouTube (https://www.youtube.com/watch?v=s5kLMW7aYyM, https://www.youtube.com/watch?v=91mBNofKBmo). English subtitles are burned in, which is too bad as I would have liked the opportunity to practice my French comprehension. (I was amused when one of the characters shouted in untranslated English, "What the fuck?")
I was intrigued reading about The Substance, but figured I wouldn't be able to stomach the body horror, so was glad to read of this earlier effort. As one who has spent a lot of time making avatars of myself for video games and other online media, I could somewhat relate to this concept. Though I would never want to have a physical operation as portrayed, I could see society getting to this point with implantable VR devices, and then discriminating against those who did not opt to use them, à la Black Mirror. Unsettling, but possibly inevitable.