I am not sure it is that easy with NAC. Anecdotes are often incredible.
It is a (weakish) biofilm buster, scavenges aldehydes, interacts with heavy metals (iirc positively) along with what you already mentioned increasing glutathion. There is alot more to it and i think its magic as with most things lies in the right application at the right time.
Most chronic ill people i speculate have a bad persistent infection going on where NAC has its place.
In that sense it would help the energetic situation as its helping dealing with toxins and pathogens. As for a more general statement in healthy people i could see it being a net negative?
Even more so what one should consider doing to offset negative outcomes that could come with longterm use (ive been taking it for half a year now)