I would say we don't really know if it's so called Long COVID. I mean that I have taken care of an ME/CFS sufferer long before COVID was around. So it's a set of diseases grouped by their similar symptoms. Autism and ADHD seem similar in that regard
Modern understanding of autism / ADHD sees the two as part of a spectrum of neurodiverse conditions (think of an audio mixer of many different traits, more than a side-to-side slider), but I don't see the connection with ME/CFS, whether or not it's caused by a covid infection.