Uh, yeah. Words mean things. You don’t get to redefine them when someone points out that you are using them wrong.
Right.
Merriam Webster dictionary.
Definition of myth
1a : a usually traditional story of ostensibly historical events that serves to unfold part of the world view of a people or explain a practice, belief, or natural phenomenon
The events are not PROVEn yet. Hence myth.
Kozak is right, a myth is not NECESSARILY untrue even though most people seem to think so. Joseph Campbell explained it all in his book The Power of Myth.