Girona squad composition is not perfect like Madrid, so currently Girona is better off letting the Copa Del Rey go rather than losing the opportunity to get the La Liga Trophy, if Girona forces to target all competitions then I'm sure their squad will fail to win the trophy Considering the composition of the players they have,
Of course you are right Girona players are not on the equal performance with real Madrid because irrespective of the fact that Girona is on the first position on the league table doesn't mean that they are stronger than real Madrid because I'm confident that if real meet Girona there is every possibility that they will likely win Girona because even on there last meeting real Madrid won them so perhaps just like you said the best thing Girona should do is to focus all there energy on this Spanish La Liga instead of dividing there attention because if they are not consistent enough this time and real Madrid manages to take over the first position Girona will mostly find it very difficult entering the first position again.