Owning 'decent' headphones does not translate into experiencing / having 'decent' or great sound quality.
I've owned some decent headphones in the past
In the past I've plugged my headphones (e.g., Sennheiser hd600, Grado RS2e, etc) directly into my phone or laptop and it's been fine.
To get a handle on whether "it's fine" purchase an Audioquest Dragonfly Cobalt or Red, connect it to your MacBook (you may need a connection dongle, depending on your MacBook version) , and connect your headphones to the Dragonfly. You may need to select your audio output. Mostly plug and play.
Consider this a starting point. There are many options and paths to move forward with. The return / rewards are significant.
Experience a taste of what's possible. Then choose your next steps.
All the best. - David.
+1 re @nekoaudio