And what does the Bible say that Jesus did for the 36 hours between death and resurrection, other than be dead? But then He was not dead. How did He resurrect, other than through His own power. But that required a conscious act of will, which implies that His soul was still alive, somewhere. Contemplating Christ's activities for those 36 hours is about as fruitless as contemplating where anyone goes when they die. There's only one sure way to find out. The rest is a waste of earthly time.
Peter at Acts 2:32 said God resurrected Jesus but if you feel this thread to be a waste of your time there are lots of other threads.
One primary lesson from Christ is that He did nothing for Himself, but only in obedience to the Will of the Father. When He sought to perform work, He performed this through God the Holy Spirit.
The doctrine of the hypostatic union provides outstanding guidance on how every believer is to remain faithful through Him, humble before God.