Actually if you look at Girona at the moment it is not far from the performance of Betis last season where they were also quite surprising at the start of the season but slowly they lost their balance and in the end the conditions remained the same they were only in the Europa League. Girona will also not be much different even if they try their best now but their condition will only be a dark horse and be in the Europa League zone at best in the Champions League position 4. But to be in the championship zone and compete until the end will be very difficult for them.
You are right that currently Girona only acts as a dark horse, because in order to survive it doesn't look balanced. However, when talking about the leader of the standings, you have to look at the mentality of the players. Just relying on early season performance alone doesn't mean Girona can lead La Liga. The La Liga competition will be very powerful in terms of energy, mentality and strategy, so this requires the Girona coach to be able to compete with coaches like Ancelotti and Xabi and even Simeone also needs to be used as a reference.