Look… GIVING EVERY SINGLE PERSON IN AMERICA THE SAME DAY OFF DOES NOT WORK, for a number of reasons, all given to you in this thread.
It makes more sense to regulate the length of the work week and work day (as is done in places like France).
The issue of social isolation isn’t just due to overwork, there are many other factors (like people not living in walkable communities, less public space, loss of third spaces, the lack of TIME due to long work weeks, the shift to socializing online, etc). It’s not just that people have to work on Sundays. that’s just an absurd and easily disprovable argument.
FORCING everyone to only take one specific day off a week, that doesn’t now allow for differences in circumstances, isn’t going to do what you want it to do. It’s going to punish some people in a variety of ways (again, go read through the push back you’ve gotten).