The best book on the subject is “The Search for the Ark of the Covenant” by Randall Price.
The honest answer nobody likes to hear is “no one knows.”
And no, it’s not in Ethiopia. They have a Middle Ages Christian treasure chest behind that veil.
The Ark of The Covenant has been in Heaven, as noted in Book of Revelations, see link. In Old Testament, it disappeared and was protected by God himself. Second link explains that history of Ark of Covenant.
http://biblehub.com/revelation/11-19.htm
https://www.gotquestions.org/ark-covenant.html
I’m inclined to agree, but I’d not heard that about a treasure chest before. Where did you get that from?
I think it's more, "The people who know, aren't talking."
But what do I know? :-)