The Presocratics are usually understood as primarily rejecting mythical accounts and turning to rational ones. This is true, but it needs to be taken strictly. It is a very different thing to reject (or downplay) myth and prefer reason than it is to say (as it often is) that philosophy must concern the things of reason alone. These things are so different that one might even go so far as to claim that one rejects myth because they recognize that there is a reason to be followed above human reason (this seems to be Plato’s argument in the Republic- we reject the poets when they lie about the gods, and tell only human stories).
The Presocratics (or even the whole of Greek Philosophy from Thales to Plotinus) does not tell us what to do with revelation, nor does it establish human reason, as human, as the supreme authority in philosophical discourse. In fact, the whole of Greek philosophy seems adamantly opposed to both the idea that human reason is the highest reason, and that man can live well apart from the divine aid.