Is it considered a lie not to inform one's mother of the true reason for reducing working days, given that informing her would lead her to force her daughter to return to full-time work, and that the daughter wishes to dedicate herself to memorizing the Quran and seeking knowledge?

The question contains two matters: First: Reducing working hours without the mother's permission is not blameworthy, especially if it is due to the son's need for rest or for seeking knowledge, as obedience to parents is not obligatory in matters that harm the child. Second: Reporting something contrary to reality (lying) is not permissible, and fears of insults and humiliation do not justify it. Instead, one can use tawriyah (ambiguity). The questioner must repent and not return to such actions.