https://www.merriam-webster.com/dictionary/whilst https://www.merriam-webster.com/dictionary/whilst The definition is singularly, "while", with no extra connot

https://www.merriam-webster.com/dictionary/whilst https://www.merriam-webster.com/dictionary/whilst The definition is singularly, "while", with no extra connotation, other than it is as you said chiefly British. https://trends.google.com/trends/explore?q=while,whilst https://trends.google.com/trends/explore?q=while,whilst "While" is, not surprisingly, much more widely used, "whilst" being more affected.