By the Will of Chingis Khan (2009)

Three childhood friends. Three sworn brothers. One was initiated into the sacrament and grew up to be a great shaman. The other two followed the path of war and the nation recognised them as leaders. But only one of them was to become the ruler of the entire steppe. He was chosen by the Eternal Blue Sky and the Sky itself put him on a trial. Love for a woman will make him a warrior. Allegiance to the law will lead him to fratricide. Striving for peace will force him to start war. The council of nine tribes, speaking nine tongues, proclaimed him the sovereign and gave him the name of an ancient deity - Genghis Kahn.

Unfortunately the movie By the Will of Chingis Khan is not yet available on HBO Max.