Tx fees has nothing to do with the wallet you use to make the tx, all the wallet does is estimate what could be an appropriate fee, but since some wallets are 'bad' at estimating the fee, you should check mempool.space before making your tx. You pay tx fees to the miners and this fee is not set or fixed by any particular person, it is the 'network' that determines the fee, in the sense that if the mempool is congested fee rate will rise, but if it is less congested fee rate will drop.