No, there is currently no fee to withdraw money instantly from online casinos. Any fee charged is specific to the payment methods and right now, UPI, Paytm, Netbanking, and Cryptocurrencies do not charge any fee for instant withdrawals.
Please bear in mind that this may change in the future, at any time the service providers decide they want to levy a charge on withdrawals. But you don't have to worry about incurring any withdrawal fees as of now.