I would say this.
Drives forward with the ball, yes. Opens up space, yes but only in midfield. Works hard, sometimes but mostly yes. Has a great shot, no chance. He produces a banger every now and again but he is not a goal threat at all. It’s one of his weakest points. If he was better in the final third, he would be one of the best midfielders of his generation, but alas he’s not so he’s a just good midfielder
He’s essentially a first third and middle third
player. Very press resistant, loves coming deep to collect passes from the keeper or fullbacks. If the idea is for Kovacic to come off the bench, then I get it but I don’t think he’s good enough to replace what Gundogan gives you.
That said I will be gutted so lose him especially to a team in the same league.