There was a recent video of a person in a situation similar to yours — I believe it was posted to Reddit, either in /r/hobbycnc or /r/shapeoko… and there are posts here more recent than 5 years…
Hearing damage is cumulative and irreversible, so I quite agree w/ keeping things quiet.
The biggest bang for the buck on quieting things is to decouple the machine from the floor (and don’t let it touch the walls) — say a foam sheet and vibration isolating pads