I was in Istanbul for a wedding and stayed the following week and worked remotely.
Bartu and his friends in the bars and restaurants in Besiktas were super friendly and helpful from arrival to departure.
The apartment is great. Has everything you need - dishwasher, ac, washing machine etc. The internet connection is great as well. Doing remote work incl Zoom calls was no problem at all. Bartu had stocked the fridge with bottled water and shops are literally a stones throw away in Besiktas - an amazing part of Istanbul that is always busy with restaurants, bars, shops and life in general.
I highly recommend staying with Bartu in Besiktas