What is the ruling on leaving an accounting job that takes 16 hours a day and prevents one from seeking sacred knowledge, given the current unavailability of an alternative and the prospect of marriage, or is it better to postpone marriage and dedicate oneself to seeking knowledge?

Our advice to you is to keep your job unless there is a Shariah prohibition in it, and to seek knowledge at other times. Combining both is best if you are in need of the job. Prioritize the obligatory knowledge concerning matters of faith and acts of worship, and choose a discerning, رباني (divinely guided) شيخ from among the Sunnis. As for marriage, if you find a way to protect yourself, do not delay.