I work 12s on a surgical neurosurg floor. I have worked nights most of my 16 years of being a nurse, plus I pulled nights when I was in the navy. Honestly it has never been a big issue for me.
I was a night owl as a kid, so it’s just a natural extension for me. however.. If I was going to suggest to someone how to adjust.. You have to pay off a sleep debt to stay healthy. So if you work 12 hour shifts on Mon, Tues and Wed ,then you need to stay up late and sleep late on your days off. It keeps that circadian rhythm in check. I would also suggest melatonin or valerian to help you with sleep during your nights that you work.