Otamendi leaving is still a big if. Valencia did move on Murillo to Sampdoria for loan + obligation to buy at €15m. So they definitely have a spot spare and do need a senior figure who can play regularly and rotate with Gabriel, Garay hardly offers any competition, Diakhaby is their young centre half so Otamendi alongside him would be ideal for them. Everything is in place but Valencia will still struggle to match our demands imo.
A deal could still be worked out, but I don't see us being able to afford Koulibaly, maybe someone else.