If the kick is recovered by R anywhere on the field, it belongs to R. In this scenario, if the ball is not touched by R beyond the LOS, then it depends what down it was when kicked. If it’s 4th down, and the recovery is behind the LOS it’s going to be R’s ball regardless who recovers, because the line to gain was not made. If it wasn’t 4th down, if K recovers behind the LOS, it’s K’s ball and the down counts. These all assume a recovery, but no advance.