"MaXXXine" is a direct sequel to "X" (unlike "Pearl" which sort of stands alone). In it, Maxine Minx gets a role in a legitimate film called "The Puritan 2" (a sequel to "The Puritan") and is anxious to finally become a real star. However, her past from the events of "X" start to catch up to her when a detective (who is working for a mysterious man) finds her, and among the backdrop of the "Night Stalker" slayings in Los Angeles, people around Maxine are starting to die...
"MaXXXine" is far the weakest of the three "X" films. That's not to say it's bad, but it doesn't have the real horror and novelty of "X" and the "can't look away" suspense of "Pearl." The person behind everything is pretty obvious, and there are really many threats that are simply too quickly and easily resolved, so much of the suspense is limited. Goth is great, as always, but there really isn't anybody else in the cast that really stands out. And there is a real lack of actual "horror" in this movie. "X" was a great, flat out horror movie. "Pearl" was more horrifying, perhaps, as opposed to pure "horror." But I'm not sure "MaXXXine" really qualifies as a "horror movie" at all. And the ending... meh.
I have no hesitation recommending "MaXXXine" -- the story is interesting, Ti West is a wonderful filmmaker, Maxine Minx is a great character, and Mia Goth is great in the role. But as is the case in more trilogies, the first is clearly the best and each one decreases in quality.