What is the Sharia ruling on working as a legal representative for the National Bank of Agriculture and Rural Development, knowing that the salary is paid by the National Employment Agency and not directly by the bank?

Do not take a job at an interest-based (usurious) bank, even if your salary comes from another source, because working in interest-based banks falls under aiding in usury, which is a major sin. Scholars have issued fatwas (religious edicts) prohibiting working in them because all bank employees cooperate in sin. It is permissible to work in them only out of extreme necessity if you cannot find another lawful job to meet your basic needs, provided that you search for another job. And whoever fears Allah and relies upon Him, He will provide for them a good and lawful provision.