I haven’t read the book, but I’ve watched the TV series. I really like it. I think the commentary on modern Christianity is the main point of the story so everything else comes second really. I would contest your argument that the show isn’t representative of Christianity today. I think it very much is and while it may be a bit exaggerated for effect, I don’t think it’s that far off.
Additionally, all the other stuff is unrelated in my view. Doesn’t really matter how the power grids or nuclear silos are being managed? No, that’s not the point. They do imply in the series that the former U.S. territories have been fractured, referencing battles and rebels in Chicago and other places as well. I think Gilead, according to the show mainly exists in the Eastern half of the country.
I will admit though that the show has certain style and it’s pretty intense at times so it may be not for everyone, but I don’t think it’s bad at all. Furthermore, the points its making about religion today are much needed caveats.