Normally, Jehanne, the legitimacy of a pope needs to be known with the certainty of faith, as a dogmatic fact. Given that you clearly do not have this certainty, as evidenced by the mere fact that you're even asking the question, as well as by your statement that there are arguments for and against it, you are, like myself, what I have termed a sede-doubtist.
In the case of a Papa Dubius, one can for just reasons break from submission to such a one. There's a theological maxim that a doubtful pope is not pope: Papa Dubius Nullus Papa.
In fact, most Traditional Catholics, if you dig deep enough, are sede-doubtists. If you ask them to think and to say honestly whether they believe that Francis is the Pope with the same degree of certainty as they believe in the Immaculate Conception (i.e., with the certainty of faith), only a very very dishonest person with an ax to grind would say yes.