Very worrying you're a teacher with those viewpoints
Clinically, "neurotypical" means someone whose cognitive/neurological functioning falls within the range that doesn't significantly impair daily functioning or meet diagnostic criteria for conditions like ADHD, autism, dyslexia, etc. It's a functional/statistical category.
Saying "an awful lot of people struggle with varying degrees of executive function however" is spectacularly missing the point. that's exactly why ADHD is diagnosed by degree and impact, not by whether the symptoms exist at all. The bar for diagnosis isn't 'do you ever struggle to focus' — it's whether executive dysfunction is severe, persistent (present since childhood, across multiple settings), and significantly impairing daily functioning: job performance, relationships, safety, finances. 'Everyone has some of this' is like saying 'everyone feels sad sometimes' to dismiss clinical depression.
Then this little nugget you left us with "“ADHD can also be caused by external factors such as chronic stress, trauma and abuse in childhood.” No, this is not true. Childhood trauma/complex PTSD can produce symptoms that look like ADHD — poor concentration, impulsivity, emotional dysregulation, hypervigilance mistaken for distractibility. This is a real clinical challenge (differential diagnosis), but overlap in symptoms isn't the same as one causing the other. ADHD is a neurological condition. Heritability is around 70-80%, among the highest of any psychiatric condition — comparable to height. It's linked to differences in dopamine regulation and structural/functional brain differences, and it's typically present from early childhood, often before any trauma could account for it.
By the way, its very clear that you are just parrotting Gabor Mate's opinions. Opinions that are completely unsupported by clinical research and data. If you are really teaching ND kids you need to get off Instagram and do better.