Vacation
The sage told him that the resources would arrive in ten days, which means that during the next ten days he would be completely free
There is no more pressing matter to do in this world anymore, no wars... no conflicts... nothing.
He destroyed every obstacle in his way, and he destroyed everyone that might have been an obstacle in his way...
And the family's future was secured with all those resources and knights.
There is simply nothing left to care about.
As someone who had come out of crushing mental exhaustion due to successive wars, and then entered into long retreats to discover and write the Blaze Heavenly Law Cultivation technique without a single day of rest, Robin felt he desperately needed vacation during those ten days.
But what does he do with them? ...Maybe spend them with his four adopted kids?