Tia has a beautiful apartment that I benefited from staying in for nearly six months so experienced at very different times of the year - I liked it so much that I just kept extending. The place is very attractively styled, spacious, calm, and everything from the kitchen to the bathrooms work very smoothly: I had not a single problem or issue across the whole period of my stay. The location is one of the nicest in Kreuzberg, with the apartment looking out on the most open section of the canal, and a great selection of restaurants, bars and shops are very close by, as well as good public transport connections (Tia has identified many of the best options on a google map collection she provides).
The apartment is comfortably warm in winter and cool in even the peak summer heat. Openness to the street (it has its own separate entrance too) is a real asset - easy to step out, watch the world go by or have friends drop by to say hi but can easily be closed up for privacy. It can work very well in multiple guises - as a work-space, entertainment space, or fantastic base for exploring the city. It was equally great in the most extreme phase of the lockdown and the super-open, summer-by-the-canal phase. Friendly neighbors in the other apartments. Bedroom to the back is very quiet and although I didn't sleep in the front bedroom, the street outside is really not very busy (most of the foot traffic is a few steps further away at the canal). Tia is very nice, communicates well, lives nearby if there are any issues.
Probably the best Airbnb I've stayed at (I have already planned my return...)