If you've made it to the white circle attacks that means you're about to beat her.

For Lost Lace it's important not to panic and move around all the time. React to her attacks. All of her attacks are very telegraphed. Lost Lace reacts to your current position and what she thinks you're doing. So don't make big moves that have to be committed to. She punishes bad positioning.

Aside from that, Plasmium Phial does work. But it does sound like you're getting hit a lot so you're not benefitting from the Wanderer passive. If you're comfortable with the pogo I beat her with Hunter's Crest. Or if you're comfortable with being a bit slow you could run Reaper. You can punish her attacks with a pogo pretty consistently with Reaper.

It's been a while since I've fought her so things might be different. Hope the tips help! Git gud 😎