Girona have been great in the last two seasons. But when it comes to trophies I agree with what you have said that it is still quite difficult for Girona. What differentiates Girona from Madrid or Barca is that both teams have quite good squad depth. Playing a fairly busy match between La Liga and the Champions League certainly requires consistency in the game. And if the reserve players are not as good as the main players, it will be a problem if some of the main players are injured. So apart from good performance, consistency is also needed to become a champion.
Girona's quality may only be good for La Liga and to measure how well they can manage their busy competition schedule they will have to try to get a place in the champions league next season. I agree that every team must have reserve players who are as good as the main players and that is what Real Madrid and Barcelona currently have, so however, Girona, with the depth of their current squad, I don't think can match these two teams in the title race. Being able to finish in the top 4 is a very realistic thing for them.
I am confident Girona will finish in the top four to qualify for the Champions League next season, but I do not believe they can win the La Liga trophy because only Real Madrid and Barcelona are the best clubs in the league that usually win the league trophy, and I believe Real Madrid will win the tittle this season because they are already top of the league, and I believe they can lose points against Barcelona this weekend because Barcelona will not allow them to defeat them at home, Because Barcelona are still focusing on the league they haven't given hope and they still have a chance to win the league because the league hasn't gone far this season, and they will like to win the match and get three points against them, and if Real Madrid defeats Real Betis in their next coming match, they will lead Girona by a clear three points in the table.