ADHD is a neuro-developmental disorder, not a mental health difficulty. But it has the same lack of parity of esteem!
There may be a slight increase in incidence, but this is unlikely to be a significant contributor to more people seeking diagnoses. As with autism, it appears to be a combination of things including more awareness, less stigma, and maybe COVID times that gave people opportunities to notice new things about themselves.
Closing waiting lists is unforgivable