What is Network fee
The blockchain's charge for processing a transfer; it depends on the network and congestion, not the amount.
Network fees go to validators or miners, not to the exchanger. They are paid in the network coin: TRX on Tron, ETH on Ethereum, TON on TON.
Sending 10 USDT and 10,000 USDT on the same network costs about the same. An exchanger may include the fee in the rate or deduct it separately.