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.
I think we are talking a bit more about Girona, Girona have been performing well recently but Real Madrid and Barcelona have been performing well overall so I think we should talk more about Real Madrid and Barcelona. Girona have started well in La Liga but they will not be able to sustain their good start into the mid-season. As consistent teams I see Real Madrid Barcelona and Atlético Madrid who can be consistent from the beginning to the end of the season.
Girona's performance will continue to deteriorate when facing tough opponents. Although Girona is in a good position in the points table, at the end of the season you can see either Real Madrid or Barcelona in the first position in the points table, the competition will be between these two clubs.
Like the previous season Girona was also quite surprising, but at the end of that season their performance dropped drastically so they didn't get any tickets other big competitions in Europa. This season their performance is better than the previous season, it's quite impressive that in 9 matches they can be able collect 22 points, that's actually a good record. But yes, there is no guarantee that Girona can continue to be consistent until the end because their track record is not very convincing.