Because Helm of Obediences ability only stops milling once it has either milled X cards or a creature, if you have a replacement effect in play that exiles cards when they go to the graveyard, the Helm never sees either of its conditions met, and it just mills the entire library
If your Commander deck wants, say, 38 lands, you shouldnt play 37 and a Maze of Ith
He still has the Apostles Blessing and Rangers Guile, but hes only dedicating two slots each to this choice
Here is a look at the Elesh Norn, Mother of Machines variations that can be found in ONE Collector Boosters
Its a conquest that has played out over the course of Disney Lorcanas first three sets of cards, including The First Chapter, Rise of the Floodborn, and Into the Inklands