Once every race has been completed at least once, the players can now access all the races within a series from the series festival. For instance, after a player has completed all of the road races at least once, they can now go to the Apex Festival and be able to load into any road race of their choosing without having to fast travel. Then, once the chosen race has been completed, the player will be sent back to the road race selection screen at the festival so that they can immediately start the next race of their choosing.
Essentially, it is the street racing hubs from Horizon 1, only applied to each racing festival (Apex, Wilds, Baja, and Street Scene). This is meant to streamline the post-campaign experience, especially for players who tune in for the racing and can’t be bothered with the open world every time. However, this is also why all of the events must be completed at least once prior to this feature being unlocked, so that the open world doesn’t go to waste at the beginning of the game.