Another website which is closed on Sundays is https://www.baby-dump.nl/. The site used to be really "off", but nowadays you can not order anything, but still take a look at what they're selling.

Babydump has 12 brick-and-mortar stores around the Netherlands.

I've never seen anything like this before. They've got 8 showrooms in the Netherlands, so it's not even a small company. This is the translated message on their website:

"Dear visitor, Thank you for your interest in our organization. From our belief we keep Sunday as a day of rest in honor of our Creator. For this reason, all our business activities are shut down on Sundays. We hope for your understanding and are happy to welcome you on our site or in our showrooms on the other days of the week."

Consider what "Sabbath Mode" might look like for a web browser — would it just pop up random sites every ten or fifteen (this delay could be configurable until Friday?) minutes, slowly scrolling through them?