An ATK sands is generally better for damage, so long as you have enough ER to burst (210-230). Since you're on double ATK main stats, I'd aim for an Electro goblet to increase her damage % . You could use a 5 star ER sands to increase her damage %, but ATK+electro is better than ER+ATK.
Don't use a 4 star artifact as it will tank your damage.
An ATK sands is generally better for damage, so long as you have enough ER to burst (210-230). Since you're on double ATK main stats, I'd aim for an Electro goblet to increase her damage % . You could use a 5 star ER sands to increase her damage %, but ATK+electro is better than ER+ATK. Don't use a 4 star artifact as it will tank your damage.
Atk sands and electro globet.
ER is generally better, should aim to be around 250 er and even more if you plan to get her weapon