John 20:1, “Now on the first day of the week
Mary Magdalene came early to the tomb.
It doesn't seem to me that John is claiming that marry went by "herself".....the text doest say that she went alone
If I tell you that Joe had lunch in McDonald's yesterday....... Am I saying that Joe went to McDonald's by himself? (Not necessarily)
John 20:2, “So she ran and came to Simon Peter and to the other disciple whom Jesus loved, and said to them, ‘They have taken away the Lord out of the tomb,
and we do not know where they have laid Him.
In this text John is implying that there where other people apart from marry (note the We) if marry would have been alone she would have said "I" not "we"
So it doesn't seem to be a contradiction to me.....mentioning one person doest necesarry implies that there was only one person.
The phrase
"Joe whent to McDonalds " doesn't becesary implies that he went by himself
"Joe saw his friend Ted at McDonalds " doesnt necesairly implies tha ted was the only person that joe saw, nor that there where no other people at McDonalds
"JOE talk to Ted" doesn't implies that Joe only talked to Ted during his lunch time
In other words
If person 1 claims "Joe whent to McDonalds",
And person 2 says
Joe whent to McDonalds with his wife, ......
nobody would call this a contradiction....we all understand that authors ted to omit details hay are considered irrelevant for the purpose of the story.