Holy shit!, I actually never seen photos from the German side during the Battle of Berlin, this is a great find. Shame it has the watermark, but great find nonetheless!.
There are more pictures from Berlin in the physical BPK archives, but they are still sitting on them. Anyway, some of those previously listed images have been released in some publications (
http://waralbum.ru/wp-content/uploads/2018/12/Berlin_1945_StG-44_ZF-4.jpg) and you can always buy images from BPK, if you claim to be working on a small print. They just need to know about the layout (for each image) and the est. print size. They are not keen selling images for private use, even though it's fine through little bureaucracy.
Berlin, early May 1945