Krishna is a deity or an incarnation of a deity. Maybe there was a real person tue figure was based on, but the Krishna of religion is mythological. And, no - mythological doesn't mean non-existent.
Thank you. All these concepts do make it difficult to really know what the other means. Spiritual life is because of this much more tricky than material life to communicate.
To me:
Krishna is an Avatar: incarnation of the Divine with more Divine Attributes then "normal" people, who lived ca. 5000 years ago.
Deity and mythology is all confusing to me. Too many different definitions.
Deity = God
I like this definition. Keeps it simple. Though God is still beyond definition
Myth:
1) a traditional story, especially one concerning the early history of a people or explaining a natural or social phenomenon, and typically involving supernatural beings or events.
2) a widely held but false belief or idea.
So according to 1) a Myth can be true, although when involving "super natural" beings, impossible to grasp for "normal natural beings" (if super means beyond), it might be hard to believe to be true
So according to 2) a Myth is false
Confusing, but nice that all options are open. All can choose what to believe. That's what belief is about anyway
Reading all this I do remember why I like Advaita so much