If you get longer flex lines and shape them in an inverted U, or maybe a loop, then insulate to the top of the rise, then it will do two things. Keep the heat from passing into the cold line, and save energy.
Heat is rising by convection into the cold line. It can only rise, not fall.
Not to be picky, but wouldn’t it be more correct to say that hot water is rising by convection?? If I remember from physics class heat only flows from hot to cold. Heat isn’t affected by gravity as it doesn’t have mass but hot air and hot water are.