Julia Ducournau’s Titane is not an explicitly trans movie, and the lead character Alexia is not a trans man. Although she spends a large portion of the film disguised as a man, the purpose of this in narrative is primarily to disguise her identity after committing a string of murders, and there’s no real indication that she specifically identifies as male. While the character at no point reads as transmasculine, her entire narrative is filled with subtext of gender dysphoria.
Transmasculine or not, though, it’s undeniable that gender and sex play heavily into the narrative of the film. At the heart of Alexia’s narrative is her pregnancy - among the things that are seen the most innately female - and a big part of her disguising herself as male involves the hiding of her pregnancy. Just as she binds her breasts with ace bandages, she also binds her visibly pregnant stomach, which becomes more and more difficult as she progresses further along in her pregnancy. A large amount of internal conflict stems from her trying to hide her sex while blending into an all male workplace.
A somewhat loose connection can be made between Alexia and the protagonist of the 2000 Canadian horror movie Ginger Snaps, in which puberty is portrayed akin to a lycanthropic transformation. Unlike Ginger Snaps (and predecessors like Carrie), it is not the female puberty process which is displayed as the source of the rage, but rather, a fully developed, adult woman going through pregnancy. The two of which are closely tied - female puberty (which is often marked as the first menstrual period) is essentially the body preparing itself for pregnancy. Pregnancy is essentially the end result of a body developing as female.
But what if that development isn’t wanted? What if what one wants for one’s body is not what’s happening? What if there’s nothing you can do when your body changes and changes and changes, and people are pointing at you as it changes, and they see you as something you aren’t, and you don’t want this to happen, but oh my, it’s happening, your breasts are starting to get larger, people are looking at you different, you’re carrying a life inside of you just like your mother did with yours, isn’t that strange? Can’t I stop it?
Even in a context that isn’t explicitly trans, it’s hard not for a woman disguising as a man to not overlap with the experience of trans masculine viewers. Lou Sullivan’s book “Information For the Female-to-Male Crossdresser and Transsexual” (often thought to be the first book of it’s type for trans men) mentions films like Yentl, Ingmar Bergman’s The Magician (where Ingrid Thulin spends a good amount of the film disguised as male), and Girls Will Be Boys. Titane is no exception. Alexia’s fear of being exposed as a woman is one shared by a lot of trans men who attempt to go “stealth” (meaning, living publicly as a cis man and trying to hide trans status), even if her reasons aren’t exactly the same. As different as her self-understanding may or may not be to a trans man, the experience she has is nonetheless one that we connect to.