I make use of other exchanges to swap my coins but do not make use of coinbase, if you think the are charging you a more higher rate for any order opened, then why not consider on others for trial attempt, they could be reasonable to an extent, just as some have discovered that the fee placed on any coin could vary based on the coin itself and the amount coinbase set for it's exchange.

On what pair you are trading? Is that BTC/USD fiat or it's crypto to crypto?
Maybe the fees when trading with fiat are much more expensive than trading with crypto to crypto. Have you tried USDT pairs?

I no longer using Coinbase long time ago so I'm not sure about their exchange fees.
I tried to research but it seems that Coinbase's taker's fee is 0.6% and the maker's fee is around 0.40%, which is pretty high compared to other exchanges that offer below 0.1%.

I think it's a good idea to use Coinbase for trading unless you have a lot of capital because they have tier levels. If you have a large amount in your wallet, the fee rates are different.
Look at here: https://exchange.coinbase.com/fees