Agree Zubimendi is definitely worth a punt (assuming he's willing to leave Sociedad) but Kubo? I'm really not sure how the latter improves our current squad other than to add to the numbers.
Kubo similar to Grealish can get goals and assist but controls a game more. But the opinion in Spain is Kubo can turn a game when he wants to , can be unplayable. If he was at a bigger club his numbers could improve. He just glides with the ball. With Grealish injuries he could be a great replacement