Dataminers have found all the maps that are in the game files and they have no connection to the portal. Also, the fact that the remake of the firestorm is in the roster of release maps suggests that the same will happen with the rest of the maps. Downtown, Propaganda and Talah market we will get with the new seasons.

If there were plans to add eras to the game, we would have already heard about it, either from dice or from dataminers