Midfield three (3-5-2) rather than front three (3-4-3) has been a recurring topic on here with several of us thinking that a 3-5-2 would be the preferred option at some point.
Midfield three I think we need at least one player capable of a proper final third attacking impact. Or two players capable of sharing that work. This to make it a "front 5" when attacking.
Right now, imo, Ndombele isn't capable of that (and the defensive work needed in a three). Lo Celso might at some point, but not sure. The two of them as box to box players, perhaps at some point, but time will tell.
Hojbjerg, Skipp and Winks are full of running, but short on real quality in the final third to become that fifth attacking player.
Alli is the key to making that midfield three work. Enough stamina, enough attacking quality, enough defensive work rate. Lacks quality in buildup play so perhaps either Ndombele or Lo Celso is needed in a three too. But perhaps the structure under Conte will make it possible with two of Skipp, Winks and Hojbjerg?
Either way, for me, right now. Midfield three if Alli plays, otherwise front three. Up to Alli to show that he can perform consistently enough in that role.