Is it permissible for a son to ask his father for more money, given that the father is well-off and gives his son an amount that the son deems insufficient to cover his basic expenses and needs as a university student, and does the Hadith "You and your wealth belong to your father" apply to this situation?

Your father must spend on you with what is reasonable as long as you are poor and unable to earn a living, including being preoccupied with necessary studies. If he refuses, then involve your mother or other good people. If he does not respond, then it is permissible for you to take from his money without his knowledge, only what is reasonable, based on the hadith of Hind bint Utbah. Do not resort to courts except in extreme necessity.