Is it permissible to work in large usurious banks with the aim of acquiring the necessary experience to develop and benefit Islamic finance?

Your desire to develop Islamic finance indicates your sincerity to the religion, but usury is one of the greatest sins and constitutes waging war against Allah the Almighty, for Allah the Almighty says: {O you who have believed, fear Allah and give up what remains [due to you] of usury, if you should be believers. And if you do not, then be informed of a war [against you] from Allah and His Messenger}. And a trainee in usurious institutions is not free from falling into sin, whether as a consumer of usury, or its giver, or its scribe, or its witness, and all of these are equal in sin. Therefore, serving the religion does not justify falling into this sin. Usurious systems can be studied theoretically and applied in Islamic institutions.