In a brine cure, 30 days it about max especially if there is much sugar involved because the brine will get scummy and ropey. Nitrite is fast acting and safety shouldn’t go past 30 days in a brine. Dry rub is different and we can push the ppm of nitrite up to 625ppm, but in a dry cure that goes long, you need to control not only temp but also humidity 70-75% minimum but not over about 80%. This controls the drying process. Cure #2 has both nitrite and nitrate. Over time good bacteria break down or reduce nitrate to nitrite. Only bacteria if present can do this. That releases more nitrite for longer cure times.
Dry aging meat requires a fou skin like a Umaidry bag or collagen sheet to protect the surface of the meat so it doesn’t dry ring and stop the drying process in a refrigerator. In a cure chamber you need a casing like a beef bung it bladder as a casing and control humidity.
Clear as mud?