Is a loan with a diminishing interest rate of 5% (reaching 3%), such as one million Egyptian Pounds to be repaid as one million and thirty thousand Egyptian Pounds after one year, considered usury or administrative fees?

As long as the loan is repaid with an increase stipulated in the contract, it is a usurious and forbidden loan. Indeed, it is among the gravest of forbidden acts, whether the increase is large or small, fixed or diminishing. It is not permissible to claim that it is merely administrative fees, because it is not a fixed amount, but rather a diminishing percentage.