Don't know whether Southgate should be criticized here. The reason he selected Phillips is the same stubborn reason he first snubbed Grealish. Playing 3 traditional centrebacks, and having declan rice alongside phillips in midfield, this formation asks both the midfielders to be more advanced than Phillips is used to under Bielsa. He can't control the game, because recycling of possessions does not go through him. 7 players whose primary duties are defense, the only links between the front three and the rest of the team are the two wing backs.
So unless Southgate is wiling to switch to a 4-3-3 type with only one holding midfielder, Phillips will not flourish for England, and 10 like Grealish will never have a role in the team. Not that I think Grealish is international worthy anyway.
When Phillips dropped back to provide a passing option, he was ignored. So he became the decoy in taking away an opposition player to create space. And when he was subbed off, England struggled to retain the ball and move it further up.
His passing was also crisp. Better than say, TAA.
I understand the system is to take advantage of wingbacks like TAA and focus on the flanks to get the ball as often as possible to England's best players Sterling and Sancho. To me, it takes away too much in the middle. What he tries to achieve can be done with what Bielsa is running with Leeds. Kane is better than Bamford, TAA is better than Ayling, Sterling better than Harrison etc.
Managers live and die by their philosophies and tactics. And they should. But if he's not willing to make changes, Kalvin Phillips shouldn't be wasting his time and energy during international breaks.