Must the landlord's rent and the brokerage commission be paid, given the multiple problems with the apartment, the threat to life from the neighbor, and the landlord's negligence, knowing that the apartment was in our possession for two months, one month's rent has been paid, and the agreed-upon payment is three months in advance?

The lease is a binding contract and can only be rescinded for a valid excuse. Scholars have differed on the rescission of a lease due to bad neighbors. Some considered it a defect that allows for the return of the leased property, while others did not. Among what was narrated from Imam Malik - may Allah have mercy on him - is that a house can be returned due to bad neighbors. Ruling on bad neighbors and what entails from it requires a Sharia (definition) judge, and this ruling applies to the remainder of the contract period, not to what has passed. As for the commission, it is due to its owner upon the completion of their work, and this varies according to agreement and custom.