User blog comment:TimeShade/The Crisis Has Arrived/@comment-28109177-20200115045408/@comment-27640688-20200115045608

I think the way to understand that last scene is that the multiverse basically got rebooted. So there is a new Earth-2 that has Stargirl on it. As for the old Earth-2, it was destroyed but parts of it could have merged into the pieced together Earth-Prime.

However, all of this is my speculations and assumptions after this.