I mean for the biggest interdenominational threat that Runterra has seen we don't actually see that much of the void in game. It's currently 6th smallest faction, only carried by Kassadin being seen as part of the Void Faction instead of a Shuriman despite his updated lore making his powers purely based on his relics rather than actual void corruption (similar to how Jinx is a Zaunite while most prominent in Piltover). if this wasn't the case, the Void would be tied for 2e smallest faction in the entire game.
And even while being the such a small faction, this isn't the actual void in and of itself, of the 8 champions currently affiliated with the void, 2 of them (Kai'Sa and Kassadin) are actively fighting the void and Malzahar is simply a misguided profit not knowing the true nature of the faction he's serving. Leaving only a mere 5 actual voidborn champions in the game. Leaving the "biggest threat in runeterra" feeling pretty damn small.