The imperium receives vital aid!!!

They receive 2 million space marines(BUT WAIT, THERE'S MORE!!) Each of these will have the best traits of adeptus costodes and the grey knights. Each will have the psykik ability of Varro Tigurius, not only that, but they will have artificer Armour with void shields and spears that can cut through the Armour of a banblade like butter.

Assume that everyone in the Imoeruim is okay with this, how well does the imperium do?