Why not make an Indian version of the King Arthur legend?
Obviously, it would make sense to film an Indian version of the King Arthur legend if casting Dev Patel (a good actor) is the end game. It is a fictional story.
The same idea applies to Anne Boleyn with Jodie Turner-Smith, tho not fiction. Why not make the entire cast black and/or various races and/or set the film in an imagined world. Not unlike the 1990's version of Richard III, which was set in a fictional version of England in the 1930's.
Let's go back even further. In the 1960's Laurence Oliver really wanted to play Othello, so much much that he did it in blackface, which was really stupid. He could have set it in an African nation where he played a white Othello.
So why weren't those movies made? Hmmmm. I have my own thoughts , but I will save then after others have posted.