I spent a month in Heinz's apartment. It's very well suited for long-term stay, everything you need is there (for both basic and advanced cooking, cleaning, washing, stable wifi for home office). There are two nice restaurants downstairs for takeouts (because of covid), mall of berlin is 5 minutes walk, gallery Lafayette is 10 minutes walk away.
The apartment is very big, it's on the top floor of the building. There is no balcony, but nice big windows in every room.
The apartment is very central, and Tiergarten is right there for running or walking.At the same time it's not noisy, also both bedroom face inner Hof (no cars).
Communication with the host was wonderful and timely. Thank you Heinz!