"So much for something" is a common idiom used to express disappointment or frustration with the outcome of a situation. However, if you want to add variety to your writing or speech, there are several synonyms you can use in its place. One option is "that's that," which conveys finality and resignation. Another choice is "there goes," which emphasizes the suddenness or unexpectedness of a negative event or result. "No dice" is also an informal alternative that implies the failure to achieve a desired outcome. Ultimately, the best synonym to use will depend on the context and tone of your message.