One must be clear that Atlatl of Reality was a Sui Generis Enlightened Primordial Relic that held the weight of Noah's Infinite Reality and it didn't represent a damage equivalent to the shattering of a Reality, with the main question at this juncture being whether the weight of the Infinite Reality was comparable to the explosion of the shocking force released by a shattering endless river of Reality.
Among the abilities of the Atlatl of Reality, there already existed some that could directly deal out 1 True Reality Damage Value…with some abilities being elevated to be capable of dealing 2 or even 3 True Reality Damage Values with the recent infusion of Realities that directly changed the mass of the Infinite Reality!
There were many abilities under the Atlatl of Reality as this time around, Noah didn't use the strongest one that would provide the highest True Reality Damage Value- but one that would eradicate all his chosen enemies in one strike.