Q.New peach tree leaves
This is my first season with this peach tree. It is young, the trunk is only 10″ round. Two weeks ago it was beautiful and full of gorgeous pink blossoms. They have fallen and the tree is full of new leaves. Upon inspection today, I see that the leaves have what looks like red blisters and many leaves have already withered and look dead. What should I do? This is the 2nd week of new new leaves.

This sounds like the fungus Peach Tree Leaf curl.
Here is a link with more information and how to treat this fungus.
https://www.gardeningknowhow.com/edible/fruits/peach/peach-leaf-curl.htm
https://www.gardeningknowhow.com/edible/fruits/peach/common-peach-diseases.htm