Qiqi build recommendations
Qiqi's Burst has an 80 energy cost with her skill not generating any energy until [C1]. Energy Recharge will greatly benefit Qiqi, while her Burst should be kept as a last resort.
Qiqi's Burst allows other characters to maximize DPS field time while offering healing from being off-field. At Ascension 4, her Normal Attack applies the healing talisman onto an enemy with a cooldown of 30 seconds.
Regarding Weapon and Artifact Choices
Tenacity of the Millelith allows Qiqi to give the team a decent ATK boost while staying in enemy melee reach with Skill active. Sacrificial Sword increases the uptime of her Skill, which in turn increases the uptime of the team's ATK boost. If you find that your Qiqi's heals are often more than enough, you may consider switching her to this artifact set. Do note that other characters might utilize Sacrificial Sword more than Qiqi, such as Xingqiu, Kazuha, etc.
This ranking assumes Qiqi does not get her Elemental Burst up often and is instead relying mainly on her Elemental Skill for healing. If she is in a team which funds her enough energy particles, or if she acts as the on-field DPS, this set can overtake Tenacity of the Millelith (4).
Artifact stats priority
atk% er atk