The BBC article from 2023 mentioned that trauma/stress can cause ADHD-like symptoms.
My brother and I think we 'may have' ADHD. We're both over 60 and won't be seeking diagnosis, but are both suffering increasingly persistent malfunctions as we get older. Our childhood was traumatic, then, as adults, the effects of that rolled up into more traumatic episodes.
If you have a full-scale NHS assessment, the psychiatrist will look for situations that may have created long-term behavioural and/or emotional issues, which can mimic ADHD and/or autism. A clinic taking a couple of grand off you will only look at your symptoms to see if they match the diagnosis.
Like most old people, my bro and I feel it's just as useful to know ourselves and our weaknesses, doing our best with what we've got. We both had successful careers in fields that thrived on intense focus followed by creatively messing about, and didn't care very much if we were late because time blindness works at both ends of the day.
I could go for pages, but my point is that individual quirks were considered normal before society decided that quirks are pathologies. There were kids who malfunctioned severely - those children received intensive therapies, some of which were unhelpful but at least their needs were recognised as intractable.
What I'm saying is that I agree with the PPs suggesting ADHD and autism are being over-diagnosed in younger people, while there may also have been many undiagnosed in older generations.