The measurements taken by the watch can be viewed over time in the Health app on iOS. Try image searching for "Environmental Sound Levels" "iOS" "Health" to get an idea of how it looks. e.g. here is a screenshot: https://www.idropnews.com/wp-content/uploads/2023/04/Apple-H...

It sounds like this iOS app can write noise levels to the Health app too: https://apps.apple.com/us/app/niosh-sound-level-meter/id1096... so maybe that could let you test drive this if you don't already have the watch.