The accent is certainly dramatized, but then - it is a dramatization. Anna's real accent does have that Russian-born/German citizen/somehow also a valley girl quality. Hers isn't anywhere near as stark, but that's because she isn't having to imitate it.
I knew about Anna years ago from the article that serves as the backbone for the show, and I still find it incredibly wild that she managed what she did. I think the show did a good job characterizing everyone as well. As in real life, nothing is black and white. No one is entirely guilty, no one is entirely innocent.