Hey Dr. Hax, not sure if helpful but I looked in my handy dandy book on this kind of thing: it could be European Brown Rot. I looked at all the stone fruits diseases and this looks most like what you have there. I’ve included page 56 on it.

In my orchard, to build immunity, I was always a fan of neem oil and learned of its use (and a lot of other very good knowledge) from studying Michael Phillips’ books on orcharding, The Apple Grower and Holistic Orcharding. FYI Ahimsa is a good brand that I used. Hope that helps.