Small family looking for a home

Hello all, I‘m giving this another try - perhaps some of you are looking for a Nachmieter/Untermieter from July/August. (We don’t necessarily need Anmeldung!)

We are a Hungarian family of 3, have been living abroad for many-many years (7 in Berlin) and we are looking for the next place to call home. I am a freelance journalist and cook, joining the world of working moms in August and my partner is managing short-, and midterm rentals. We both have stable incomes, significant savings and own apartments in Budapest that we are renting out too. We love music, good food, lakes and seas and we have a wonderful one-year-old who is just discovering all the wonders of the world now - we travel a lot (6 months+ a year) and love coming home to a peaceful, clean, cozy home.

The place we are searching for should have 2,5-3 rooms and should preferably be in Neukölln/Britz, Tempelhof, Schöneberg. Again, no Anmeldung necessary for us!

Would be grateful for any leads because designated sites have failed us. Thank you!