Another key point is that Jose hasn't bought a single defensive player yet. He has 12 or 13 defensive players in the squad, from GK's through to holding midfielders, and that's a very loose definition of explaining our current midfielders.
Jose has only made a few defensive decisions. The first was Toby's contract extension. The second was promoting Japhet. The third was getting Dier's head aligned to being a centre half. Another was perhaps not messing about with the full-backs even though he can't be overly happy with them. It's not as if he has many options.
He must know that he has to churn half of those 12 or 13 players before anything major can change at the club defensively. If it's possible, churning 2 or 3 in this summer window is a must.