First thing you have to know is this apartment is NOT a luxury apartment. Just before this, I stayed at a shared accomodation for one third the price and it was so much better. This house looks like it was decorated in the 1980s. Nothing warm nor luxurious about it. Arek is also an extremely poor communicator.
I asked for tips on Istanbul and he said he would give me some tips but I never received any. There was also only one towel for us two guests and and only one very very thin pillow per person. We asked for extra pillows and towels and he replied with a monosyllabic "okay", but failed to provide any other information. We had to reach out to him again in the evening and then he told us it was downstairs in the basement. We found the towels next to dirty linens in the laundry room. When asked about pillow he completely ignored us.
The only time he texted us again was to ask about my checkout time. When we told him our checkout time and where we would leave the keys, he again ignored us.
The apartment is in close proximity to Istiklal but I would advise solo or females against staying here as it is a really quiet and dark back alley with lots of abandoned/vacant buildings.
Overall a really bad communicator, old apartment and not very welcoming. I would advise you to stay somewhere where the host is happy to host you and enjoys communicating.