I agree with you in principle, but CB's of this standard are as hard to get as strikers. I genuinely don't know that we can attract a CB at any price who would be good enough to walk straight into the first team, no risk and play every game.
So my worry is - we sell him for £10M and spend £40M on someone who is really no better.
So you're worried we'll waste the money? That's a different issue, and not a massively convincing argument to keep Funes Mori. It will be interesting to see who Silva/Brands identify to sign in defence.
I'd say we need to be targeting a Davinson Sanchez type. Someone with massive promise in a European league, who might be a bit raw initially.
I'd also persevere with Keane. Still think he can come good in the right defence with the right players around him. Last year was not reflective of his true ability, imo. And since people are giving passes to Klassen etc for a fresh start (rightly), I think Keane should be afforded the same.