Alex's place is great and has all the amenities to accommodate a long stay. It is a full 1 bedroom unit despite the listing saying it is a studio. We stayed for 4 weeks mid Aug - Mid Sept. 2021. The location is phenomenal if you are trying to avoid the touristy carpet seller traps better know on the European side of Istanbul. The neighbourhood is very local with cafe's and restaurants galore. All within walking distance. You can get to the famous Kadiköy Market in about 8 minutes on foot and no more than a 20 min walk you can be in the trendy Moda neighbourhood. Both the ferry and metro terminals are within a 10 minute walk from Alex's place.
The only negative that I can mention of the place:

This is only an issue during the hotter months of the year and is in no way a reflection on Alex. His listing clearly states that there is no A/C and we knew that going in. We were there for the last 2 weeks of August and it can get unbearably hot in the unit. We didn't mind during the day, but even the overnights were hot. We purchased a fan to mitigate that. Once September came around like a miracle the days and the evenings cooled down and we didn't use the fan from that point on, and even started using an extra blanket at night.
All in all, Alex's place is fantastic and a great value. I would highly recommend staying here and when we make it back to Istanbul I would not hesitate to stay here again.