Is it permissible to complete studies in another state that requires travel without a mahram, given the impossibility of finding a mahram, and the threat of abandoning studies and marrying if studies are not completed in that state?

You should convince your parents to allow you to study in your own country. However, if they insist on you studying in another state or abandoning your studies, and you need to continue your education, then there is no harm in adopting the view of those who permit a woman to travel without a mahram, as long as the travel is safe. It is permissible for a questioner to choose from among the valid differing opinions.