Sorry but with what boat technology would the folks from this African Kingdom cross the Atlantic ? I seriously doubt a canoe is realistic - because it if were, America would have been discovered by numerous countries thousands of years earlier.
Their possession of North Arab ship-building techniques, understanding of Greek geometry and mathematics, and knowledge of navigation makes it at least plausible they reached the Americas.
Given that the islands throughout the Pacific were colonized by repeated expeditions via sea canoe, it seems downright possible.
Unfortunately, that's where the evidence falls flat. Given that only four of the thousands of written Maya codices survived, there's no written record.
Given the environment, the ecosystem has reclaimed much of the land where the cities in question stood, ruling out most access to sites that may hold physical evidence.
The Mali Empire is also so poorly studied that even if we found a full Mali site in South America, it would be very difficult to recognize from above, even with state-of-the-art LIDAR to see through the vegetation.
Hawaii, it should be noted, is a clear contender for "most remote place on the planet", given the lack of even small islands outside of the Hawaiian island channels for thousands of miles.