if theres anything i hate the most from antis (aside from the harassment, of course), it's the concept of characters being "childcoded".
characters being coded as lgbt etc. originally came about because of marginalized identities often being censored- so creators wanting to include such characters in their works pretty much had to be less obvious to the average non-marginalized person, but more obvious to those within those communities.
children are... marginalized in a way in that they tend to be treated as less than human by many adults, but not in the way where they get censored out of everyday media. there is no need to code a character as being a child because, most of the time, you will not be prevented from just making a character a child.
"Child-coding", more often than not, also actively infantilizes neurodivergent adult, both in media and (by extension) in real life, by pointing out traits in adult characters that are common in those who are neurodivergent, and painting them as a child. There is no need to " child code" things, all you're doing is performing far more harm than good.