It is based on the oppression of women in the 19th century and also, about equality of women in societies. Undoubtedly, this touches the topic of feminism and liberation as you mentioned. The woman who was locked in the room basically represents all women in society who struggles for equality. However, the wallpaper reflects what the main character and women was going through. By stripping the wallpaper down, the protagonist believed that she could earn her freedom, which indeed happened at the end. The cracks and markings on the wallpaper represent the tears of women and the color yellow represent death (dying). The bed represents their marriage and the woman she saw behind the bars in the wallpaper basically is a projection of herself and redundantly, the women in societies during the 19th century. Moreover, it can be noted that is the unjust dominance of males and also males (John, her husband in this case) represents obstacles that women faced (note: the movement for women rights is also a possibility).
The bars on the window represent the unjust barred freedom of women in society too. It was more like a prison room rather than a recovery room, this again represent society and women and how it can cause a transformation of someone. However she gained her freedom (identity) through insanity in the end and as it was very ironic since she was supposed to stay in that room in order to recover. Also, this story represents the author in real life. She went through a very similar pattern in life. Moreover, when she saw the woman creeping, the narrator did not like this--that is, not for women to creep in society. However, some women is ok with this, like her sister-in-law (