Structurally I think Ederson, Stones Dias Cancelo Rodri, Foden and Bernado are really the key 7.
Kevin and Gundogan are great. But they both cancel each other out. While we are better with both playing, there is no drop off when one plays but the other doesn't. The style changes a bit, more risk and chances with Kev, more control (and lately goals) with Gundogan.
Mahrez is rising with his recent performances and wi easily join the list if his press stays up. Which leaves us with 0ne Question really... Walker or Zinchencko?
Eddy, Stones Dias Cancelo Rodri, Berny Foden, Gundo, Kevin
So if you want more possession and interplay you play Zee and sit Walker at fullback. If you want a tougher defender and more athletisn and speed you play Walker and sit Zinchencko.
If we want a Striker and stronger press up front you sit Mahrez and play Jesus. If you want technique and control and greater 1 v 1 play Mahres and sit Jesus.
Everyone else is a backup until further notice.
Those names are less "structural" and more based on consistency.
On the list that Billy shared in terms of our structural players, I would remove De Bruyne. I think Ederson, Stones, Dias, Cancelo, Rodri and Gundogan are the key structural players. If any of those aren't in the team then we do lose something (generally).
Ederson - obvious reasons
Stones - solid defensively but also carrying the ball out from defence and enabling space for others
Dias - obvious reasons
Cancelo - our best inverted full back, so creative and vital to how we look to play now
Rodri - obvious in terms of being a key cog in the side. Not always consistent but still a vital structural player
Gundogan - regardless of where he plays he is the one that keeps the ball ticking over and finds pockets of space to operate. Works best when allowed a freedom to move further forwards in my opinion.
De Bruyne I would say is not a structural player. We played some brilliant football last night with him interchanging as a false no 9. He's class of course, but I think he can be swapped in/out of the team more than any of the above without a change in result. I'd have him in it still as much as possible.
Foden and Bernardo are excellent players and I think when Bernardo is on the pitch we get the best out of Mahrez in particular because they are both so good on the ball and so hard to defend against. Foden similarly has so many strings to his bow and makes life incredibly hard for the opposition.