Does the death of a person who was unable to purify himself from ritual impurity (janabah) before death indicate Allah's wrath?

There is no evidence that a person dying in a state of janabah indicates Allah's wrath upon them; rather, the opposite has been proven. Handhalah ibn Abi 'Amir was martyred on the Day of Uhud while in a state of janabah, and the angels washed him. The Prophet, may Allah bless him and grant him peace, asked his wife about his condition, and she said: "He went out while in a state of janabah when he heard the clamor." So the Prophet, may Allah bless him and grant him peace, said: "That is why the angels washed him."