@Aradia I'm happy to say that right from the start, this has been a big part of the game @orrery is running. Well, it certainly has for me! Please accept my ramble. *grin*

My character has eclectic special interests (sculpture, radical expressions of identity, turning herself into a teapot), a significant speech impediment (by her people's standards), a habit of being inconveniently honest, and the occasional meltdowns when shit that doesn't make sense comes at her too fast... yet she has a CHA of 14 because she holds a moral code centered around compassion and inclusivity, she doesn't bullshit people, her magical cyborg limbs are expertly crafted to look non-threatening, and she has the uncanny glamour of a fae being.

In her somewhat idyllic culturally-isolated homeland, her own people find her lack of tact, hopelessly out-of-tune voice, and odd way of emoting to be anywhere from quirky to repellent, and her appearance is plain except for her unsettling aftermarket parts. She gets serious about the strangest things and upset over what seems like nothing. Among her people, she is a neuroatypical oddball, and her Charisma acts more like an 8 except for a few really good friends.

To the outside world – so many people weary from subterfuge and war and general bullshit – she's a cute little unicorn whose exotic accent, kindness, and killer design sense make her unusual perspective and frank nature that much more appealing. Who could stay mad at a cute little unicorn? (Bad people, that's who!) Away from home, folks don't react to how "weird" she emotes – most bipeds don't expect to read emotions on equines that way. She doesn't sound "weird" because the local language isn't rigidly tonal. Interactions start friendly and tend to stay that way; folks don't see her behavior as off-putting because they don't have a reference for how unicorns "should" act, or they figure it for understandable equine skittishness. Some mistake her for being someone's animal companion, right up until she speaks intelligently, then they accept that this is another perfectly reasonable way to be a person, and they treat her with equal respect as their own peers.

When she gets agitated, they don't see overreaction and they don't see atavism. They see a beautiful and gentle person struggling to stay above water in a world flooded with cruelty. When she melts down, they don't make it her fault, they work with her to find out what's gone wrong and make it right.

So, yeah, point is: Context. Charisma is all about cultural context. We're telling this story, so we get to explore what it looks like when the majority neurotype doesn't treat others as disabled and/or undesired. As far as we're concerned, CHA is for those who act with empathy, integrity, and gentleness. If there are to be low Charisma scores, they're for the swaggering assholes who won't respect that...

...or, of course, extremely noisy rough-and-tumble folks like another character at the table, an NT-coded monk who manages to be an up-and-coming sports hero with CHA 8. She's an awkward speaker who's very impulsive and aggro AF, but she gets big Charisma bonuses around her fans (a minority of people who are totally on her wavelength) and folks who are good friends because they see a wonderful person with some behavioral stuff that's totally worth learning to work with.

Bonus: Like our GM, my unicorn is on the autism side of the autism/ADHD range. She's travelling with her (GM-played NPC) gryphon lover who, like myself, is very much on the ADHD side. We built these characters as a sort of experiment to take some little steps in each other's shoes. More than once, that gryphon has said something that could only come out of the mouth of someone who deeply understands life with ADHD. Orrery says they've felt the same in return. These are magical moments, and any tears are happy ones! This is definitely a correct way to play D&D.