Unity/3d/2点間角度

var quaternion = Quaternion.LookRotation(target.position - player.position);
target.transform.localRotation = quaternion;

参考：https://www.create-forever.games/distance-rotation-quaternion/

角度を上書き

xとzを0に上書き

var quaternion = Quaternion.LookRotation(target.position - player.position);
target.transform.localRotation = quaternion;
target.transform.localRotation = new Quaternion(0f, target.transform.localRotation.y, 0f, target.transform.localRotation.w);