I could see maybe non-binary being something like this...I'm not too familiar w/ transgender issues but supportive, but binary seems to be sort of what used to maybe be a 'tom girl', though I'm probably way off on that...
But true trans-f trans-m truly are or feel they were born the total opposite gender, some may even have been born w/ hermaphrodite expression possibly, where they had some of the opposite parts which could cause hormones of that kind...
Regardless, it's not a mental health issue imho, for some it may be a decision for the non-binary types..that one confuses me some, and I'm ASD spectrum so blunt, so I hope I don't offend anyone, just trying to use reasoning to understand/talk it through...
My cousin who's like 20 years younger than me is transitioning to male via hormones, etc. It seemed odd to me, but she didn't have a very happy upbringing either, raised by grandparents and her mom/dad I think not really wanting a kid (or treating her like she was their 'child'. She was dating a girl in H.S. then a boy, who she's still with even through becoming trans, I really haven't seen her in years though, just from facebook, etc.
Honestly, I admire people who find out who they are and go for it. I'm 42, and still floundering trying to find my purpose in life, or who I am. I'm a dad, and a programmer, and a husband... but what else? I feel incomplete often myself, but that's partly trying to learn to deal w/ ASD/ADHD which I only found out I had 3 years ago, and is part to blame for my obesity, depression, anxiety, and bouts of complete lack of motivation or severe procrastination.
tldr: I highly doubt gender-id is related to tik-tok or 'contagious', except maybe non-binary only because that's a little fluid, and just logically in my head it's non-committal one way or the other, though that's probably just my lack of understanding what it really means to be non-binary... Personally, I can't fathom waking up and being like: Ooh all these men want to be girls, that sounds like fun, I should too... it just doesn't sound like something that'd be prone to peer pressure. It's definitely a very personal choice, and has reasons behind it.