Unable to answer "What are the opening hours here?" – on level 0: Konfetti (Gift Shop) – https://osm.org/node/2094461171 via StreetComplete 59.1:

Shiko Änderungsschneiderei Mo.-Sa. 9:00 - 20:00 Uhr

Attached photo(s):
https://westnordost.de/p/246335.jpg