Unregistered-Frank Parish

In your particular situation (irregular crack on wall) you might like to consider the following.
I used to be a boat builder. One thing an old builder told me has stuck with me through the years. If the break is obvious and the repair options are chancy, lood at the possibility of simply covering up the whole thing with a decorative item. Maybe the item could be far removed from the material it is covering, i.e. if the material is blue, cut a nice teak or mahogony board, mold the edges with a Roman Ogee, or some other such fancy edge, and mount it over the fault.