It depends. Longer stories can get harder if the writer doesn't manage the pacing well or if there are too many subplots. But a skilled author can keep it engaging and not overly difficult.
Not necessarily. If the story is well-structured and the narrative is clear, even a long story can be easy to follow. It all comes down to the writing skills and the organization of the plot.
Sometimes they do. Longer stories often have more complex plots and character developments, which can make them harder to follow and understand.