For me, I have been working 4 days work weeks for multiple years now, and love it. The experiment went so good that the rest of the engineers in the time have Friday's afternoon off now.
You can do this, even if your company never had this type of working schedule or even if your team still works 5 days a week. You will not be left out nor called lazy. In my case I actually deliver more, and higher quality, since I started because previously I was developing physical pain in my hands/arms (because of work and sedentary life). I have started the process of working 4 days a week in 2 companies, a big (unicorn) one that is part of NYSE, and a small one of less than 20 employees. This works on all scales (not guaranteed it works with all companies).
Shameless plug: If you want help on this, I actually have in my bucket list to write a medium/short guide or handbook on how to do this. With examples, email templates and how to approach your employer.
If you are interested, fill this: https://forms.gle/8VkGnE6Rpq86BGQa6
*You'll only hear from me regarding this book.* I won't add you to any list, nor send you anything else not related to this.