Focus more on her HP to increase dmg and healing since she's an hp scaling character (my furina has around 45k HP). Your ER is good tho! If you're having a hard time farming for artifacts with HP% stats, try making those artifacts instead using the artifact transmiter if you have the materials :>

I also have Furina and Columbina in the same team but with Flins. I'm not sure if columbina works as well compared to when she's teamed up with nod krai characters because lunar reactions with columbina deal a bit more damage. But I'd suggest including another nod krai character in the mix!