Who are you going to borrow egyptian pounds from to pull this off? The egyptian central bank certainly won't do it, and any third party is going to charge you the black market rate (ie. the true market rate), which wipes out any profits you might make.
>Usually when there’s a currency arbitrage opportunity, locals will circularly exploit the currency arbitrage (potentially by exchanging pounds with an Egyptian bank for 10% more USD or perhaps another way)
Usually you can't pull that off because the central bank won't sell foreign currency to just anyone. You have to have a valid reason, or be well connected.