Unable to answer "What are the opening hours here?" – STOREBOX (Storage Rental) – https://osm.org/node/11626814825 via StreetComplete 57.3:

There is no obvious entrance, only private flats, even though there are still pictures and the website yourstorebox.com states 24x7 and street number 47

Attached photo(s):
https://westnordost.de/p/211904.jpg