Like others, if I have had 6 hours of sleep and get up for the bathroom, that's it, I am awake and up for the day. Pointless to go back to bed.
Always been an early riser other than during a growth spurt in high school and seem to need less sleep than others. Worked well before I retired as I was usually in the office by 5:45 with nobody else and no distractions. Almost never worked late.
A few years ago, I was still asleep until about 9:00 A,M, and woke to my wife holding a mirror over my nose and mouth. No doubt, she was hoping that it wouldn't fog
I was also a "hyperactive" kid and suspect some of that is still in play as a 70 yo man. It's ok as I make it work to my advantage.