Sry, but afaik there are some flaws with this hypothesis. Neurodivergence is no defined Illness but a catch-all-term for deviations from the norm. The thing with normality is, nobody really wants to be a normalo, and only very little people fit there. Everyone has his deviations. Neurodivergence refers to mental deviations from the (statistical) norm.

Whether you Like it or not, Person A with schizophrenia and Person B with depression only have in common that they both suffer from a ICD-defined Illness. That aside, theres not much in common between the two.

Calling the ability to be mentally ill, a defining trait of humanity is kind of strange. That would make normal people less human?