I work F/T, I study ~3hrs a day, I work on sideprojects, I exercise on a bike for an hour, I do bodyweight exercises, and I have a partner and social obligations like everybody else. I also get as much sleep as I want and have a ton of free time, mainly my weekends and after work evening hours are completely free as in there isn't one thing I have to do whereas most people I know need to spend hours doing laundry and other chores they put off. Before I did this I worked F/T, wasted all my free time and felt like I had no time to even get essential things done like going to get a haircut. My strategy then was to put off everything to the weekend and then end up not doing it anyway, repeat. After I organized myself I was even working at a university lab on weekends in addition to everything else because of all the free time, putting in 6hrs before 1pm still left lots of partying or beach time.

I agree that productivity memes are getting ridiculous, like actors or CEOs who shill their schedules of getting little sleep and power lifting 5 minutes after waking up at 3am but there is benefits to doing just basic time management. I give myself 4 hours in the morning free time before the daily commute. Before I started doing this I had to blow off social obligations because homework and assigned reading were due, but now I'm already done the assigned reading, already done working through the hw (and last semester's hw), and already went through the lecture slides before I go to the lecture that day. The reading I do while on a stationary bike for one hour. The bodyweight exercises I do during 10 minute breaks while going through exercises and hw. A half hour in that morning period is just for organizing laundry/cleaning and basic chores that before I put off until the weekend, then would end up wasting half of Saturday getting my shit in order. Breaking it up to a half hour for 5 days a week, and now my weekend is completely free, which was a god send when I started doing an OS course and the assigned projects were a ridiculous amount of work like implementing a kernel spec. While I'm doing all this everybody else I know is asleep, there's no phone calls to answer, no emails to answer ect. I'm always out at night doing something with my gf and have tons of energy whereas before I just wanted to fill my face with takeout, passively entertain myself with some Netflix marathon and then pass out. I didn't have a gf, I was overweight, I was tired all the time and thought that it would be impossible to finish a chapter out of a dense math text unless I waited until the weekend, but of course I was so disorganized I didn't have time on the weekend either.

The only reason I made this choice to start scheduling was due to getting older. When I was very young I always felt like there was plenty of time to put off things until later, but like you I'm very aware of time and how little of it we all have. Now if I'm wasting time I'm always thinking to myself I could be learning randomized computation right now and discovering something amazing about quantum information theory, instead I've wasted that opportunity so I can consume yet another zombie themed soap opera. That nagging feeling of winding up on your death bed and realize you've wasted something like 12hrs a week for 2 decades passively watching junk or putting off having a family to just self indulge a meaningless existence is pretty much my primary motivation not making money or becoming a Zuckerberg.