and if your transaction is not complete or confirmed, then you can reduce your transaction fees by using mempool.
Please don't spread wrong information.
You can use RBF to replace an unconfirmed transaction, but the fee you pay for the replacement transaction must be higher than the fee paid for the original transaction.
And currently, due to the increase in the price of Bitcoin, everyone is crowding in transactions, so it is natural for transaction fees to increase at this time.
Again wrong.
Currently, miners are including transactions with the fee rate of around 3-4 sat/vbyte in the blockchain.