I made a throw away account and it says 0 fees on the withdrawal tab (
https://i.vgy.me/Mt1Xlz.png), so there should be 0 fees. Any legit exchange would always have an accurate breakdown in their withdrawal tab that says about the fees/how much will you get, so you can pretty much trust the infos there. Deducting an amount which wasn't declared before confirming the withdrawal would be a scammer move.
Also says free in here:
https://www.coinex.com/fees?tabs=deposit