From what I can tell, the SM-T555 came with either 16 GB or 32 GB of internal storage. Is that how much yours had before this happened?
This model was released in 2015, so it's 7 years old. It wouldn't have gotten any official updates after the first couple of years, so which firmware did you use to upgrade via Odin? If you used a firmware that wasn't designed for your specific device, it might have caused this problem.