'Could care less' is imo the preferred formulation, the implication being that while there is no fundamental physical law preventing me from caring less, from a practical standpoint it seems highly unlikely. It's like how I could be a high lottery pick in the 2023 NBA draft - I'm unathletic and old and get humiliated by 7th graders in games of 1-on-1 - but technically it only takes one NBA GM seeing something special in me and I'm shaking hands with the Commissioner.

It's all in the delivery.