The basic construction here is ne {verb} que {subordinate clause}.

point here underscores the ne, making it more absolute; in this sentence you can remove it or replace it with pas or better pas du tout without really changing the meaning of the sentence.

In this construction, que is usually translated except or only.

So, que je n’espérais point pouvoir acquérir qu’à faux titres could be translated that I never hoped to be able to acquire except by false pretenses.

You are missing faire peu d’état, which means to make light of, almost to ignore or try to ignore or belittle, nothing to do with “state”, and celle which refers to the gloire. Descartes speaks of his métier in the previous lines, he hasn’t stopped. So, *even though I did not make it my work to cynically despise glory, I nevertheless thought little of that glory that I never hoped to acquire except by false pretenses”.

In my humble opinion . . . I could be wrong about what celle refers to, it could be the profession (métier more than declaration).