Lol. Kalvin Philips would've been struggling with Leeds United in the Championship if he had not leave for Manchester City. Besides, it would be every players dream to work with Pep Guardiola so why stay with Leeds United when you can work with the best coach and manager? With his qualities when they first retuned to the Premier League, he should've made it to Pep Guardiola's first team but how can you drop Rodri for Kalvin Philips? I would consider Pep Guardiola insane!
With the Euro's approaching speedily, most players with less game time are on the move because they'll want to impress for the next six months. That's so they could be picked by the managers of them countries.
Maybe I talked nonsense there.

It was too much to ask from Kalvin Phillips to be a part of Leeds in the Championship. But he can at least join a team now at which he can find many more chances in the starting eleven. It is very difficult for him to do that at Manchester City now as you have also said.
He is a talented midfielder so he shouldn't just let himself fade away like this. Probably we would see some offers coming to him in even January. But I assume he would like to join a different team more if that team are competing in the Champions League as well.