So sorry to hear that your tree is barely alive!!!
The way you protect it was better than any protection I have done on my Nikita’s Gift. I don’t know what had gone wrong? How tightly packed you put the leaves in. When I packed with leaves, I packed them in very tightly before burlap.
This year, I used mulch so it is packed tightly. I am waiting for the high temp to be in the 50 p’s for a few days in a row. It arrived today but last only 3 days so I don’t know if I should remove mine yet.
I could not remember where you bought your tree from. It is possible that iy was a wrong tree, the less cold hardy one.
@tony or others who know more about cold hardy persimmons could chime in.