So instead of taking on a kabala, they should take on the mitzvah.
Any form of strengthening your Avoidas Hashem, whether by enhancing your performance in one area, or by accepting to be better in other ways, is equivalent of a “Kabbalah”. Saying a brachah on food with more kavanah; being nicer to somebody who needs friends… or anything that you weren’t doing as well yesterday – that is a Kabbalah.