Just saying because nearly every person I know who has ADHD and/or Autism (including myself) seems to care less about people knowing they're into "childish" things.
Also the idea that this is a new phenomenon because Millenials and older gen Z are "soft" or stunted in some way.
I mean, boomers have model trains and and cars. So did their parents. My grandma used to knit herself plushies. This isn't new. You don't suddenly stop having your old likes because you reach a certain age.
Absolutely nothing wrong with having hobbies or being into childish things but to me "manchild" shit starts to arise when you start doing shit like gatekeeping your hobbies from women and poc or attack anyone trying to make it inclusive. Disney, Nintendo, Marvel et all are billion dollar industries after all thanks to adults flush with excess cash.