Being able to play Discard spells is the best way to stick a midrange plan in modern, and Inquisition of Kozilek for sure suit that plan really well
Underworld Connections added to your devotion and gave you more cards at the cost of life, which is exactly what Gray Merchant needed, since it both wants you to have a lot of permanents and can gain your life back
Once this creature is prepared, you then wait a turn around the table to be able to cast Channel
While Belakor is very tactical in the lore, this card doesnt want you to think, just run in and smash
Turning on Delirium is actually fine: Mishras Bauble is played in the format and together with fetches, cantrips and creatures its not a problem
If you begin the game with this land, its not much different than having a Mox Diamond and definitely signifies that youre willing to trade resources to turbo ahead of other players at the table