Okay, I need get this info dump off my chest: I think the deal with the vakif stuff requires some explanation that cannot be fitted in T/Ns, so here it is.
Normally, a woman in the Ottoman Empire was not allowed to establish her own vakif (waqf) unless she was the valide sultan (mother of the sultan) or the daughter of a sultan, preferably married to some influential state official. All the other palace ladies were nothing but slaves, and they had to know their place as such. And even when women founded vakifs, they were almost never in Istanbul, but in other parts of the empire, mostly where the sultan stayed as a governor when he was a prince. Having a vakif in the capital was considered to be a privilege only enjoyed by the sultan or very influential grand viziers. When imperial ladies built mosques/established vakifs, they were either in the provinces or rural parts of Istanbul at best. So Hurrem breaks two taboos: She establishes her own vakif before becoming the valide sultan, and in Istanbul at that. Well, Galata is not technically in the old city, but it's right across where the palace is (I think this vakif in the manga is fictional though, I couldn't find such a place in Galata. If someone knows, please do tell me). So, like, wow. That's why everyone is scandalized about the vakif stuff.
Fun fact: Hurrem actually established a vakif inside the old city walls later. There is still a hospital there, and that neigborhood is still called "Haseki". And the hospital she established was one of the first and biggest health institutions in Istanbul. How cool is that? I didn't know why that place was called Haseki before 😅