This has been known for decades (probably as long as the 5 day work week has been a thing)
And this is “fine”. Because not everyone has the same slack day. Hell, at my current job, me and a buddy outright acknowledge this and he takes the brunt on Fridays when I am just done with everything and I do Mondays when he is usually distracted with whatever his kids told him they need last minute.
Same with meetings. Some weeks, the ONLY thing I do on a wednesday is go to a few meetings. Or maybe me and someone else set a friday lunch meeting because that is the only time we both have a chance, and so forth.
For people who have “real jobs” where they actually work hard (so retail, construction, etc): You tend to not get the “easy” day for the most part. You are busting your ass and being overworked all week long.
For office workers and the like? I think there should be a lot of thought put in. Someone doing data entry might not need to be there all five days. Someone who is doing more design/planning role… we already end up working closer to 6. And efforts toward “flex time” and just general “We don’t care when you are ‘at work’ so long as you are available for meetings and get stuff done” go a long way toward that. Because, for example: I busted my ass for what amounts to a 20 hour shift yesterday getting stuff working for a customer. Today? I am basically checking my email but made it clear that even that is “I might not answer”. And I’ll probably take a few afternoons off next week to even it out.
But, with the shit world we live in: that would map to people who “don’t have to work all 5 days” getting paid 20% less. So pretending you are busy on a Friday afternoon is probably still the better option.