The Sabbath was given to Israel before the rest of the Law, while still on the way to Sinai (in Exodus 16), because it was Israel’s introduction to the Law. Among many other ways, the Sabbath introduces the Law by teaching, in an especially clear way, some key but often neglected principles of legal interpretation. Here I look at three examples.
I agree with your point that it's not necessarily a great idea to think of the laws instrumentally.
I wrote a post about the benefits of observing a Sabbath and I'm curious for your perspective! https://trailblazingtwenties.substack.com/p/a-power-of-sabbath-time-blocking