Here’s an interesting article that discusses the authenticity of the 1417 Chinese map. Contrary to what you would concluded from watching this show, the map’s authenticity is far from being verified. On the contrary. It contains anachronisms that disqualify it on its face.
https://www.nytimes.com/2006/01/17/world/who-discovered-america-zheng-who.html
History Channel Said it was St. Brendan and the Irish who discovered America https://www.history.com/news/did-an-irish-monk-discover-america