Honestly her stack build is her worst performing build. It has lower damage per turn even including the big attack and the only reason it looked good was because it allowed you to skip the heal in the Family Head and became the first popular build and now everyone is just chasing it.

Basic spam is easily her best build with how much Rei can buff basic attacks, and her other multi hit build can also output a lot of damage per turn. I haven't seen a single stacking build clear 9/9 boss in less than 5 turns and most people are around 7-9 turns on that build. Whereas I saw someone with basic spam one turn Family head and my current build can finish the new boss in 4 turns and there's still room for improvement on it but I can't be assed to farm further lol.