Apples rotting on tree
Looks like you have a myriad of summer fungal diseases like bitter rot, black rot, and/or white rot. Warm summer temps and rainfall exacerbate all of these diseases. Take a look at this UK IPM scouting guide for apple here: http://www2.ca.uky.edu/agcomm/pubs/ID/ID219/ID219.pdf
Also, here's a simplified UK spray program for backyard apples: https://plantpathology.ca.uky.edu/files/ppfs-fr-t-18.pdf
One extremely important thing to remember about sprays , especially in large tree fruit like apple, is the importance of coverage. If you don't get good coverage, you won't get good control. And if it rains after you spray, you have zero protection.
Hope this helps.