What is the ruling on working in an administrative position at an institution that provides loans to young people, with the possibility of it acting as an intermediary between borrowers and usurious banks, and is the salary resulting from this work considered suspicious?

If your work in this institution is free from Sharia (definition) prohibitions and has no connection to interest-based loans or facilitating them, then there is no harm for you in working and receiving payment, even if the institution's funds are mixed. Consideration should be given to the nature of the job and whether it requires signing or facilitating usurious contracts; if so, then it is not permissible to work in it. However, it is better to find another job that has absolutely no doubt concerning it.