Are the psychological harms resulting from a mother's harshness and ill-treatment, which manifest as hatred and lack of affection towards her, considered a sin? And how can one deal with a mother who inflicts harm upon others and constantly causes problems?

It is obligatory to honor and be kind to one's parents and not to abuse or shout at them, no matter what ill-treatment they may inflict. The questioner erred in her behavior towards her mother and must repent. This does not mean abandoning advising the mother and stopping her from oppressing others, but rather doing so with wisdom, gentleness, and kindness, as the Prophet, peace and blessings be upon him, said: "Indeed, kindness is not in anything except that it adorns it, and it is not removed from anything except that it disgraces it." As for the heartfelt love towards the mother, it is something the questioner does not control and is not held accountable for. She should strive to achieve it and supplicate to Allah to instill it. The mother's receptiveness to lectures can be utilized as a means to reform her, along with seeking help through supplication. The questioner should not preoccupy herself with thoughts of being punished by her children.