Are you talking about stuff like this? https://josm.openstreetmap.de/mapsview?entry=Hesse+DOP20

According to geoportal.hessen.de Hesse DOP20 is already open data and uses DL-DE->Zero-2.0 license. Though I don’t know how it is in different states/nation wide.

https://www.govdata.de/dl-de/zero-2-0

These photos already look better than what Google Earth supplies and they get updated every 2 years.

And technically it surpasses it by far. You might notice that a lot of roofs look a bit weird and pixelated at the edges. They correct the position of high places to counter the camera angle. Generally the angles are also better than what Google supplies.