The phrase "and/or whatever" is often used to express a non-specific possibility or choice. However, there are many synonyms that can be used to convey the same meaning while adding variety and elegance to your language. "And/or" can be replaced with "either" when presenting two options, or "both" when referring to two options that can be chosen simultaneously. Additionally, "whatever" can be substituted with words such as "whichever," "regardless of," "no matter what," or "any." These synonyms can be used interchangeably, depending on the context and tone of your message, making your writing or speaking a more polished and engaging experience.