Him becoming an additional central midfielder in possession is preferable to him overlapping in a side where he has to regularly use his weaker left foot. In the last two games, he has often been forming a midfield trio with the other two midfielders in front of the back 2 in a classic 2-3-5 shape
(2-3-5)
Romero-VDV
CM--CM-Spence
Porro-Kudus-Simons-LW
ST
He could also, and actually did yesterday on a few occasions, push forward to the final third when Simons or Kudus drops back to receive the ball in a deeper area.
The most glaring issue I see here is the lack of a dominant ball carrier on the left, in the fashion of Kudus, that can run that flank on his own. This is an even bigger problem if Frank is planning on playing RKM and Richarlison together, with the former being assigned to the left side. He, as a striker, would love to drift towards the centre instead of hugging the line like a usual winger.
With Spence sitting narrow as well, this could cause a serious imbalance in shape as teams channel VDV and midfielders towards that completely vacated area on the left when they're searching for a forward pass. Not ideal at all.