I am neurotypical, though I have some attributes in common with aspies like stimming, and High Sensation Seeking, while also being sensitive, and many sensory issues, particularly to bright light and loud noises, but I don't have what I understand as Autistic touch issues. I'll accept a hug from anyone, except when they don't feel safe, or their cologne is overwhelming, or whatever.
I don't think I experience meldown, but sort of something like it. Somewhere I read that the person doesn't feel it coming and suddenly finds themselves in the middle of it like an attack, and one source described it as anger toward themselves. I have no clue if that is what meltdown is, I only know what I have read, but I experience anger at myself somewhat frequently. It's like things that seem like very minor offenses cause very major consiquences. I am overly sensitive to criticism for instance, or when some oversight of mine causes me a lot of extra work, or to receive a very expensive fine, or whatever. When this happens, the problem was caused by me; some attribute of mine, like my forgetfulness, or because I misread some person's intention, or whatever, and the frustration can become overwhelming, and I sometimes take my frustration with myself, out on myself physically, I am ashamed to say. This almost never happens in public. It's not like an attack for me. I know what I am feeling and why, so I don't know if it would qualify as a meltdown.
But I identify with some of your after feelings.