The interview for the role was completely different from what I am now doing.
Isn't that the norm? Like the old joke about hell seeming to be an all-out vacation, and then it turns out that was just the marketing brochure?
I very recently landed a sweet-sounding well-paying job at a large international consulting house. Turns out, on the inside it's all gaffer tape and leaky abstractions. Not some of it, all of it. After having spent a few months sussing out the scope of the issues I determined that yes, this is unfixable by any one new hire, so I've done some interviews and will be starting a new position elsewhere presently.