If you’re going to Malaysia, just find an ATM immediately after entering Malaysia. There is at least one or two Maybank ATMs at KL International Airport for every terminal within the airside zone. It does not charge for withdrawals using Monzo, hence 0%. There’s a catch though: Be careful of the DCC offered on the ATM screen!
For more info on Monzo in Malaysia, you can have a look here: 🇲🇾 Monzo in Malaysia [Wiki]