Amusingly, there is literally not even a 7 day work week ban for companies in the US. You can require employees work every day. Employers are just required to pay employees overtime under various conditions beyond 40 hours / five days a week, which is why you don't see it.

And what's more, software engineers are exempt from these rules because of their pay grades. If you're a SWE making a salary the odds are your employer could require you work on Saturdays without running afowl of labor laws.

This is all powered by norms.

You would also need to ban them from employing people in other countries that allow 5 days work.

Same logic applies internationally.