I agree we don't need a CB unless one leaves. I doubt Ota should be that one though. He is currently the best CB at the club. And while I reckon he won't be a starter starternext year, having him as the 3rd CB. Will keep us studded at the position.
On the other hand to lay it all at Kun's feet is easy, but in truth the problem is deeper than just him. We need an 11 who can press consistently and comfortably. Meaning, Dihno energy with Silva's technique. So Isco, Llorente. Thiago's brother at Barca, Grimaldo, Henrichs. These are guys with technical skills. Sanchez to challenge and bench one of Sane or Sterling or Mbappe if we can get him. We need to push a few of our starters to the bench so we have good talent off the bench.