I always understood a myth to be something like fiction.
That is the common understanding.
In sociology the word "myth" does not imply either truth of fiction. Rather it references something that is of value to that culture which may be either true or false. Then there are those who believe that they contain both fiction and truth. So, yes, that myth can be fiction. But, it can also be true. Or, it can contain a mixture of truth and error.
A leading example of such that exists in most societies are the "creation myths." Those are generally of major value in their cultures. Some people accept them as true and some as false. But, in calling they a creation myth, there is no implication of either fiction or oftruth.
In SDA Culture, those who oppose ordination for women may feel a need to explain why EGW was given the credentials of an ordained minister, for years. The records are clear. She was given these credentials for years. But, there is no clear documentation as to why, just as there is generally no clear documentation as to why anybody was given such documentation.
So, people have come up with stories (myths) that have taken on a life of thier own as to why she was given such credentials. One such myth is that people wanted to pay her the same as an ordained minister (probably true) and there was no way to do that other than to give her the credentials of an ordained minsiter (probably false).
That myth defies common sense in the later part. The church could have taken a vote to establish a seperate catagory of pay for EGW which was equal to that of an ordained minister.