The second route is currently being built in Munich [0], with work started in 2017. I recently watched a youtube video by The B1M about rail projects in Germany that included a long section about the currently ongoing works in Munich [1] that gives a good visual overview.

[0] https://db-engineering-consulting.com/en/projects/munichs-se...

[1] https://www.youtube.com/watch?v=bPDQdnT-RaY