Most efficient way to auto transfer fiat to Binance

I would like to set up a recurring fiat transfer from my bank to Binance. I am looking for the most efficient way to do this (least fees)

I have seen that this option is available via credit card but buying BUSD costs $1.015 translating into a 1.5% fee for each transaction. I have seen that buying crypto directly also induces some fees due to a purchasing price higher than that of the market.

I am trying to implement a simple DCA strategy. What is the most efficient way to automate all that in Binance?