Opposite access to enums
There may be a more fundamental problem here beyond converting a string to enum.

By adding a fromString(String) into the enum and defining the format specific strings in the enum constructor, you are coupling the enum tightly to the data format and making it an integral part of the input parser. Your enum now has two responsibilities, being clearly in violation of the single responsibility principle

Instead you should implement a format specific converter that converts the string used in transport to the enum used in computing and make the enum as bare as possible.