I can only recommend the tour guide Mehmet to anyone. He explicitly responds to the wishes of tourists and answers all questions at any time. The guide is very nice. It is also a good idea for the tour guide to design the programme in a personal way, as the tourists, who have never been associated with the Turkish natives before, get a different view of the people of Turkish descent.
Of course, the tourists may also bring their own concerns into the city tour. The great thing about the guided tour is that you don't get lost in Istanbul, because Istanbul is constantly growing and now has up to 18 million people.
By the way: Even if many tourists are of the opinion that one can explore Istanbul on one's own, I would advise against it and give the tourists the tour guide Mehmet to the hand. On the one hand, there are a lot of open questions on the part of tourists from my point of view and on the other hand, one gets a lot of information from the tour guide that one did not know as a tourist before.