Well, not only your iPhone XS Max, but my iPhone 11 Pro experiences the sudden data loss. From what I did in the past, data recovery will become easier if you have at least one backup in iTunes or iCloud. If no, you can lastly make a further try to scan from your iPhone. The tool can be chosen as per your own needs, like D-back, Joyoshare iPhone Data Recovery, Dr.fone and more. I tried and learned that all of them have a free trial to let us preview and check whether the deleted data can be found. Hope you can get the important back!