I have traveled for business internationally as a solo woman. Although I was almost always with business groups and local hosts. I am tall, blonde, and visibly northern European.
I don’t think that you can generalize an entire city. There were some parts of Istanbul when I decided to tourist out on my own where I did not feel comfortable. But almost all the major thoroughfares and major areas that tourists would go were absolutely fine. I think you still have to keep your wits about you and be careful who you’re striking up a conversation with. Two guys pulled up in their car and invited me to go for a ride. Luckily, there was about 10 other people there, and in fact, an older woman started yelling at them. I didn’t know what the conversation was about but I think I am very grateful to her.😕
Come to the far North/Nordic. My coworkers and I can go and entire morning and say nothing to each other except work related questions and answers. It’s heaven!