I have withdrawn and trade ETH from MEXC multiple times already and I am never charged more than $3 but when I swap ETH ERC 20 on Uniswap the gas fee is almost always $10 and few times over $10, why is it like this? Are DEXs suppose to be more costly normal centralized exchanges?
high fees at dex because of the high eth fees, at the dex direct exchanger direct transactions send from the buyer's or seller's funds are subject to fees you send are also subject to fees.
while in a centralized exchanger, the fee is when you deposit, you will be charged a large fee if you use eth. while the trading fee is low. and you withdraw it later in the form of USDT not on the eth network so the fee is also low. if you withdraw it using the eth network too, the fall regarding fees will be the same whether dex or a centralized exchanger.