Peach trees are subject to a number of diseases and pests, none of which can be accurately diagnosed from this vantage point. Read about some of them here: https://hgic.clemson.edu/factsheet/peach-diseases/
You could send a sample to Diagnostic Services for diagnoses and treatment options for a small fee: https://www.canr.msu.edu/pestid/
Or you could involve a Certified Arborist, one who specializes in these matters. Find one or more Certified Arborists in your zip code at www.treesaregood.org Go to the Find an Arborist tab. Arborist evaluations are not expensive and where you can learn exactly what is going on in your tree.