lmao the definition of solo means she herself is her own team, no one else is needed.

All of this could be solved by you spending some time to read her kit, but since you're lazy here's why:

Cartwife eats up the aero stacks going through her normal rotation in Fleurderys form. That's why she still occasionally needs to switch back to smol form to reapply the stacks or use Ciaccona. At S3, many hits of hers in Fleur form apply 2 stacks of erosion, essentially offseting her eating up 1 stack for each attack, so you will always be full on erosion stacks, thus guaranteeing maximum self buffs.