After 43 days of stay, I can say that the flat is ok and that the host could be better.
The flat is nice. The neighbourhood is quiet and there are lots of shops near the flat. Be aware that is -1 floor. Also, there is no dryer and there is no gym. There is a smart TV in the flat but there is no internet or wifi.
We stayed longer than a month and we did not meet the host. She is not answering on messages on WhatsApp only on messages on Airnbn (but not so quickly).
Also, take some water before coming as you will not find even a glass of water in the flat ( tap water is not drinkable - advice from locals).
Take a photo of the flat to have proof of the condition before your stay. We did not have a nice experience regarding damage refund. The host did not come to check flat and take keys at the end of our stay as we suggested. But she asked for a refund for the things we did not touch and we did not even see in the flat.
We will come a few more times during this year to Istanbul but we decided to find a flat with a better host.