Taking turns at RB was what happened as Cancelo worked his way towards parity with Walker, so nothing new there. His appearances at left back initially came as a result of availability problems with left backs, his ability there imo much higher than was expected, when Mendy was missing, Cancelo played many more games at LB than planned but that cannot go on, he will burn out. I disagree that Zinchenko is a weaker player, he is a different type of player as clearly shown in his Villa cameo. We originally had the solid speedy Walker, the creative risk taking offensive Cancelo, briefly the physical attacking Mendy and the technically excellent possession retaing Zinny, 4 different types of players to give Pep broad tactical options. We might not find a better LB than Cancelo but Pep favours him on the right, as he said post Villa, so we need a LB replacement for Mendy or decide to move Cancelo to LB along with Zinny, and buy a RB of equivalent standard as Cancelo, then if Zinny leaves we need both a new RB & LB to maintain the 4 options, that will be disruptive & expensive.