The only possible way to change aliens plan, would be to inflict more damage/cost to them, than they would receive by their goals. But seeing as they are creatures with unlimited power, and their civilization lost any purpose or goals of such mundane things like resources, i think they will be relentless. They just want something that is special[genes/abilities] and can't be manufactured[silly game concept, they wouldn't need humans for genetic engineering, because they could engineer the ability at hand], and the cost is not a matter. Someone could compare this to USA vs Afghani talibans, but as i said above, it's not a resource war where the losses and gains are waged versus each other.
Well it is important, but we would have to inflict a losses that would have to crumble their vast empire. Destroy their colonies, threaten their homeworld, enslave them etc. But this is not a case. They have mastered the creation of matter from energy, even if we somehow destroyed their forces, they could rebuild them in matter of days.