With the consistency of Girona this season, they tried to put pressure on Real Madrid for the La Liga title for a long time. It will be hard for Girona to overtake Barcelona at the La Liga table because Girona is not currently consistent. Barcelona will capitalize on Girona's current form to lead Girona by at least four points, which will give them a comfortable lead over Girona.
This lead will not matter most times as all teams that fall within second to fourth position will have equal opportunity to participate in the champions league the following season. The first is always the priority and when a team can’t finish in the first position, they fight to finish in the top four of the table which will be a comfortable result to end the season with. Barcelona will not want Girona to finish above them because is will be a shame on them for a team like that to beat them to that second position. Since Girona have lost consistency, Barcelona will have a good chance to finish in the second place after Real Madrid.
I don't think it's Girona that is blocking Atletico Madrid and Barcelona, but Atletico Madrid and Barcelona's performance this season is quite bad so they can't put pressure on Real Madrid in the competition for the title this season, while Girona only makes a surprise without being able to put pressure/compete in the race. This season's La Liga title with Real Madrid because in terms of strength they are not capable or equal to Real Madrid.
Many expected Girona to give Real Madrid a hard time before they can win the La Liga this season and they could also be a potential target for the La Liga this season too. They started well and received a lot of praises from a lot of people, but at the end they couldn’t keep up with that consistent performance and had to give up and Real Madrid took the lead again. Now that their performance got worse, they could not even keep up to maintain the second place on the table again. It is such an unforeseen situation but at least they could finish in the top four which will be a good record for them in La Liga for years to come.