The reward for the Christian is to see God.  Then it is a delayed reward?  A gift we receive once we have been fully purified?  And brought into the presence of the Almighty?

No.  Jesus is clear that seeing God is not reserved for another realm.  “He who has seen me,” he says, “has seen the Father.”

The reward for Christian living is to see God.  When you engage in acts of mercy in secret, God will reward you.  You will see God.

But I have been charitable in secret, and I still have not seen God?

O but you have done so.  In the mirror.