What is the ruling on money earned from working in a usurious bank, and how can it be disposed of or purified, especially when buying real estate or other assets, and what should one do upon leaving this job?

You must immediately stop working at the usurious bank. As for the money earned from it: If the worker was ignorant of the prohibition of such work, then his salary is lawful, whether he spent it or it remained with him, according to the Almighty's saying: "So whoever receives an admonition from his Lord and desists, he may have what has already passed, and his affair is up to Allah." However, if he was aware of the prohibition, then what he earned is not lawful for him except to the extent of his need. Anything beyond that should be given for the benefit of Muslims or to the poor and needy.