The way this combo is structured, it is the best way to check for your opponent's Nibiru that this deck can possibly do. If they wait to Nib you when you're making Utopic Draco Future, you just lose out on a single disruption while having the gas in hand to continue comboing.

Admittedly you don't need to go the route of Gallant Granite for Nibiru, you can play Gagagaga Cowboy and detach the Goblindbergh that way as your goal is just to proc the effects of your Onomat monsters.

But the layers of targeting and destruction protection, between Starliege, Future Zexal, and the Utopic Sage in GY, are so immense that it can be overwhelming to overcome despite the lack of many actual disruptions. You can most certainly adjust the line or run additional garnets to bolster the power of the endboard, but I find that just very unnecessary as this deck can run a lot of non-engine to assist with protecting the Future Zexal, which is the primary win condition of this deck post support. If your hand is already strong engine wise, you can opt to search for the Unbreakable XYZ Barrier counter trap for a proper omni-negate.