Hi, bikemarti, I stayed at the Adina Apartment Hotel Hackescher Markt in 2022 and really liked it. There is great public transportation nearby, and if you are flying in or out of BER, you can get the S-Bahn right at the corner, which gives you a straight shot to the airport. The hotel was very nice, clean and comfortable with a friendly and helpful staff. I was a solo traveler so I had a studio room with microwave, dishwasher and fridge, but the larger rooms have washers, I believe and other accoutrements.
There are lots of good restaurants and cafes there, as well as several small grocery stores and wine shops. The Spree River is very close and the Berliner Dom is a very short walk from the hotel. There is a street market nearby and quite a few other sights in the area, including the DDR Museum, and Museum Island, and I walked to Linden Street from here. If you pull it up on Google maps, you should be able to get an idea of what is around there.
I also really liked the area. There was a nice vibe to it and I felt quite comfortable walking around by myself. Near Hackescher Markt is an interesting complex called Hackescher Hof, which is a large complex filled with shops and restaurants. It was fun to walk through, have a bit to eat and enjoy the restaurants and cafes. I would definitely stay at the Adina again.
One last note that you might find helpful is that I found this hotel by the numerous recommendations from other members here. :)
