Is it permissible to take a loan from a bank that adds an amount to the original loan under the name of "service fees" to cover employee salaries and operating expenses? And is it permissible to work at this bank?

If the bank demands an increase in exchange for the loan and justifies it as usurious interest, then it is not permissible to borrow from it except out of necessity, which is to be estimated in proportion to its extent. However, if the increase constitutes fixed administrative fees that are appropriate for the effort expended and are not tied to the loan amount, then it is permissible as a wage. But if it is a percentage linked to the loan, increasing as the loan increases and decreasing as it decreases, or if it is disproportionate to the effort expended and serves as a veil for usury, then it is forbidden interest.