I worked 4d weekday in my last job, taking every Wednesday off. I lost 20% of my salary but I loved it, the break into middle meant that Mondays were no longer dreaded things and I could do all the chores during Wednesday, freeing up my weekend to do whatever I wanted. (Also Fridays had free drinks , pre-covid)

I think the company got a good deal out of it too, as they paid 20% less for almost no productivity loss at all.