Mihoyo balances Xianyun's kit based on her traits.
She has one of the best traits combination in the game, even arguably surpassing Baizhu.
Anemo + catalyst + atk scaled + healer.
@Razor_Language
They have been putting Cloud Retainer exclusively on screen ever since Ganyu quest. Not a single Liyue event left her out. Even the 2.4 archon quest had her bragging about Shen He and judging the Qixing.
Of course she's op. They have been planning this for 3 years now.