Looking for a mid or long term apartment for rent in Berlin in the Ringbahn area

Hi everyone. Nice to meet you. We are Gleb Levi and Anna. A married couple is looking for a mid or long-term apartment for rent in Berlin in the Ringbahn area. We don't smoke, we don't drink alcohol, and we work in the creative, art and IT Fintech fields.
We came from Ukraine. I work in the IT industry as VP Product Manager for Web3, and my wife is an artist, yoga teacher, and choreographer.  The budget for rent is 650-1200 euros for entire apartment.  Also, for those who can help find the parameters with the possibility of registration, we additionally pay 400 euros as a gift for help. Ready to move in August. Thank you for your help, and support in advance.