>>533512389 (me)
Managed to get squeeze in some points by doing better and faster executions. With Carthethyia if you hold basic in her loli form she attracts enemies together. After realizing that, it became much easier to keep mobs together. I also learned that if S1 Sanhua has a 4* weapon it's better to skip her rotation and at best do a fast swap one time from the 100% concerto perk.
It seems signature character weapons are important but gearing more than the main damage dealer isn't that needed.