The Klingon boy band made the final cut, thankfully. However, they shot two versions of the Klingons, led by Bruce Horak as the Klingon captain. The second was opera. Ultimately, the opera take felt too close to the other singing. Luckily, the Klingon boy band won.
https://nerdist.com/article/star-trek-strange-new-worlds-musical-episode-choreographer-cinematographer-interview-klingon-boy-band/