If the crew had a layover - planned or unplanned - in Malaga, it was Ryanair's duty to provide them with suitable accommodation. Unless they got it, they cannot be considered "rested" for the return flight.
Unfortunately it is a design error of EU aviation rules, that they apply to everyone in principle but how they are actually applied is decided by national authorities which may or may not have an agenda of their own, rather than a common European aviation authority which could enforce a single way of reading those rules.