I share your point of view @sonnevillejr.
There is no doubt about the role of Chancel Mbemba, regarding the task of support or attack it is indeed to try.
He tends to position himself very high as you indicate, splitting quite often outside, but sometimes inside to find himself in a striker position.
As for the duo in the middle, I would tend to say that it is less clear-cut.
Jordan Veretout's role as a VOL is interesting, however, in trying to find the closest to reality, I notice that in comparison with his real role in reality (I may be wrong) he does not go off-centre in the corridor to offer a solution to the construction of the game (to be adjusted with the individual instructions ?).
On the other hand, VOL's role is interesting in the offensive game (construction, finishing) where the attributes of vision, passing are solicited meaning nice attempts at long passes in the depth.
I noticed that this last point is also associated with the role of BWM, which could therefore be an interesting role as well since Jordan Veretout generally ensures a rather intense high pressing on the field in the recovery phase and this role also contributes to the offensive game like the VOL role (less marked certainly ?).
On the other side of the midfield, Valentin Rongier clearly has a role providing cover for Chancel Mbemba's ascents.
In trying out the DM role in defensive duties I noticed that unlike the HB role the player is freer and less fixed in his movements, and more aggressive in recovery.
Moreover, he has the same behaviour as the HB role, preventing the opponents' counter-attempts, switching with the ascents of a player of a lower line (here Chancel Mbemba).
My proposal for a tactical scheme
Individual instructions : Close down more (all players excepted CD and DM not applicable), Mark Tighter (all players)