The apartment looks as advertised and Josef is quick to reply and willing to solve problems.
Unfortunately, the heater was not working and the internet was very unstable and didn't work in the entire place. The heater had to be replaced and the technicians left the place a little messy after they left.
Josef was nice to refund me for the days where the heater wasn't working and later allowed me to check-in late for better convenience with my flight scheduling. He was always thoughtful and respectful and apologized for the issues. He also offered alternatives, like switching to a different apartment, which I chose to refuse.
I do hope (and also believe) that others will not face the same issues and will be able to enjoy the apartment better than I did. Apart from these inconveniences, the place was clean, organized, and generally comfortable.