Is a person considered an apostate if they unintentionally insult the Name of Allah in the context of insulting a university by saying: "The lord of the university"? And if so, how can they return to Islam?

The default is for a Muslim to remain in Islam, and a Muslim is not declared an infidel (kafir) for ambiguous statements or actions. If ninety-nine interpretations point to thef of a Muslim and only one interpretation keeps him within Islam, then that one interpretation should be adopted. A Muslim is not held accountable for slips of the tongue that occur unintentionally, as Ibn Uthaymeen explained, clarifying that whoever did not intend to speak or curse, but rather his tongue slipped, is not held accountable for it. Similarly, the phrase "Lord of the university" does not necessarily refer to the Lord of the worlds; it could refer to the owner of the university. The matter depends on the speaker's intention and what he meant. Accordingly, one should avoid contemplating falling into apostasy and disbelief, while safeguarding the tongue from cursing and reviling.