How long before bed does she eat? Can you cut out supper?

Also, Liebs started to drop day sleeps at 16m, by 20m he was up until 10-11 if he had a day sleep. Useful for evening events, but nightmare otherwise. So maybe your girl doesn't need them?

If helping to clean isn't helping, do you have a spare bed? Just put her into that and walk away. Change sheets on the bed when she's not there, so no extra attention. Even a child's camping bed on the floor of another bedroom could work, they are fairly inexpensive.