Is it permissible for a young man to leave his work with his father and rely on himself for his livelihood and to seek Islamic knowledge, especially if his father is self-sufficient and does not encourage seeking knowledge?

You are not obligated to work with your father. It is permissible to seek another job that provides time for seeking knowledge, while being keen to please your father and be dutiful to him, and to appease him if he feels any resentment about your leaving work with him. To know which books to start with in seeking knowledge, you can refer to previous fatwas.