It doesn't only happen in every 6 hours. In every second, the gas fee is changing.
That is why when we are going to transfer ERC20 tokens, it will be very important to check the recent gas fee for transaction before sending.
And we can wait whether it seems to have decreasing fee or not.
In fact, rights now itself, the gas fee is around 153 gwei for only low transaction, this is very high, isn't this?
And commonly I will delay transferring and waiting for lower gas fee, at least at around 70gwei