Hello! I have the exact same problem, although I do have some crusting and itching once in a while in the same place behind my right ear. What I do is when I shower in the morning, I take a pair of rough bath gloves, soap them up, and gently scrape away the dead skin.
When they are absorbed, they can be released in sweat through skin. Foods like yogurt, onions, garlic, red meat, cabbage, spices like coriander, and asparagus may result in increased body odor when consumed in large amounts. When you have a diet rich in proteins, you may have vinegar like smell on sweat.
Vinegar will not hurt your feet, but you should still dilute it for the purposes of a foot soak. Generally, using one part vinegar to two parts water is a good ratio. While the soak will smell strong, the odor will dissipate after it dries from your feet. You can also use essential oils to change the scent slightly.