How can a systems analysis student at Imam Muhammad ibn Saud Islamic University make his studies and work for the sake of Allah? And is the intention to study to earn a material income for marriage and raising righteous offspring considered for the sake of Allah, especially since he does not see his specialization as greatly serving Islam and Muslims?

A person's intention to protect their chastity and to have righteous offspring is a good matter, but it should not be the sole concern of a Muslim. Allah created humankind for great purposes, such as populating the earth, reforming it, establishing the religion, and supporting the truth. Learning worldly sciences like medicine, engineering, and others is considered an act of worship if the intention behind it is to support Islam and benefit Muslims, and it is a communal obligation (fard kifayah). There is no harm in specializing with the intention of protecting your chastity and having offspring, but it is better to also intend, along with that, to draw closer to Allah by fulfilling the needs of Muslims and serving the religion. You will be rewarded for that, Allah willing. Indeed, intention transforms permissible actions into acts of obedience, and engaging in a communal obligation might be better because its benefit extends to others.