He's doing well in a counterattacking team. If you've ever watched him play, you'd know he's not great with sustained possession and therefore he'd be shit at the majority of top clubs at Europe.
Statements like "why didn't Txiki buy Kante" are quite possibly the most cancerous, idiotic things on bluemoon, it shows a complete lack of any real thought, just reactionary whinging about players doing well at other teams.
I absolutely guarantee if we had kante and they had Gundogan you'd be saying the exact opposite.