They're way too bombastic to be ambient. It's basically power metal played by a black metal band... with funeral doom song structures... and honestly, I think they did a very good job with that on Dol Guldur, even if all the songs have the same structure. It was original and they found some great melodies and hooks. However, I didn't need five more albums where they did the same thing with increasingly less inspiration.
(To be fair, I haven't listened to the newest, so maybe there are some radical shifts in the that one!).