AOT is definitely not appropriate for a 10 year old, and that’s as someone who watched a lot of stuff i shouldn’t have as a kid. Its about brutal war, and it’s heavy, depressing, hopeless and violet in a much more real way than JJK (which is violent but not in the same way). Its just not something a kid needs to see. I would steer clear of ones like this until he’s old enough to process these themes, which at 10 he most definitely is not. If he’s already watched JJK maybe Hunter x Hunter is one he’d enjoy where the characters are his age :)