As I said before we can buy him after the loan https://www.alfredopedulla.com/retroscena-kepa-promosso-sarri-ora-sconto-clausola-kovacic/
Chelsea asked Bilbao for a discount, they refused, so Chelsea decided to activate the full clause. Other targets (Butland, Oblak) are just agents sorting contracts. Real value Kovacic at โฌ60-70m if Chelsea want to sign him permanently. (After his loan.)