Antonyms for the phrase "more so and so" would include phrases such as "less so and so," "not as much so and so," "minimum so and so," "least so and so," or "barely so and so." These phrases denote a decrease or a lack of the quality or attribute in question. For example, if someone says, "I'm more hungry than thirsty," the antonym would be "I'm less hungry than thirsty." Alternatively, if one says, "I'm more stressed than relaxed," the antonym would be "I'm less stressed than relaxed." It's important to note that antonyms can vary depending on the context of the phrase.