Karma and Tanjiro are very different when it comes to personality. Karma is all about doing things his own way and defying his higher ups as much as possible. Tanjiro prefers to learn when he can from everyone and hone his skills to go as high as they can. In terms of ability he is in a completely different league from Karma though so this would be an easy win for him. The deep breathing techniques make Tanjiro far stronger than a human can hope to be. Tanjiro wins.