I hope they bond later

Those who confused about her revenge, i think i get the idea:
Her revenge is for her mother who has been tormented her so she can be a “proper lady”

Her mother has high expectations and pride for her real daughter and she wants her real daughter to claim FL hard works

So first she shows how different she was with the real daughter, so later when her mom switch their name and rob her hard work for the real daughter, they cant deceive the eyes of those nobles.

While our FL gone instead become the empress with her new name (which makes her hard work got rob),
The real daughter need to marry the crown prince, society will notice that Helga was not the real helga, so there will be a lot rumor of the duke family

The thing helga got will ve:
1. Peaceful live (she’s leaving all behind)
2. Her mother will feel pain because her own expectations (towards her real daughter, how her plans ruined) possibly she can go crazy
3. Her hard work doesn’t get stolen, because society will notice that the real daughter came and steal FL name and hard work (it will give the real daughter bad reputation all her live) well even if its not her fault

If she became the empress she will feel that she gave all her hard work to the real daughter while she need to endure all the gossip and bullshit from the nobles. The duke fam will still enjoy her successful business result.