Zinchenko will lose out on this position simply by considering our weapons of attack.
When Sane played LW, then having Zinchenko as a LB makes sense because he comes inside more often and Sane can go wide and use his pace and send crosses in, Sane got more assists than any of our forwards the last 2 seasons.
The problem is with Sane out, we now have Sterling playing LW, but he is right-footed, and has to play more inside and plays as more of a goal threat than goal creator.
This gives us a problem on the left wherein basically we offer no crosses and are really predictable, almost any cross relies on David Silva having to get behind a back line and whip one in.
This doesn't exist on our right side because while Walker is not a good crosser, Kevin is basically the world's best crosser and makes up for it.
If you consider the two ways we can set up the point is further illustrated:
Sterling
---------------------D Silva
-------Zinchenko
--------------Sterling
Angelino
---------------D Silva
I would argue the 2nd is still better in a "balance" sense because
1) D Silva is better in midfield than Zinchenko at controlling the ball
2) Sterling get's to play inside more often, and is in my opinion better at taking players on than David
3) Better cross delivery with Angelino
The downside is that D Silva has to play a little deeper and not as high up, more typical of a 4-3-3 with attacking fullbacks really, but as long as the other midfielders (say Rodri and Kevin) put in more defensively to allow Silva to push ahead, then I think that can be achieved. Same idea on other side, if Kevin pushes forward then Silva would drop a bit.