What can I do with mealy peaches?
For just you to make the palatable:
puree them. I do this and the rare occasion we end up with mealy peaches they are fine. I put on top of my waffles in the morning as a healthier alternative to syrup. You may need to add a bit of juice if they are really mealy.
Make them into a dessert - cooking them will help. I find they can sometimes be gummy, but they work fine.
No need to toss good tasting fruit just because it isn't perfect!
Slice, drizzle oil, sea salt and freshly ground pepper and roast for 20-25 mins. Drizzle with good balsamic vinegar and enjoy. Actually, I don't know that this would make the mealiness less apparent but worth a try. I did this recently with some nectarines that had sat in the fridge too long and shrivelled a little. They turned out very yummy!