"there is much more to it than that"
This can be literal, but often is used to indicate that there is additional or secret meaning.
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For example, "I thought that getting good grades in school would get me a job, but there is much more to it than that." <- This is a literal type of usage where it might indicate that in order to get a good job, I need to do things besides getting good grades, the things could be "family connection", "having experience". For example: "I thought that getting good grades in school would get me a job, but there is much more to it than that such as knowing the right person who get help me get an interview."
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Another example, "I think that they will break up their relationship because they are always fighting over money, but there is much more to it than that".
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It is NOT usually used to indicate more work or effort is needed - this would be abnormal: "I ate the first two courses of the meal, but there is much more to it than that"