This is the curse of counterfactuals you can't answer.
I was pretty directionless in my younger years, but reasonably smart and driven. I was in the Army and in my late 20s and decided to get into software and went back to school full-time while still serving in the Army. Possibly somewhat predictably, I also went through a divorce at the same time. But I was awake at 3 AM or so every single day, studying for several hours, going to work, studying at lunch, coming home, studying some more, on and on for a few years, and that was all I did. It was work of some sort, nonstop, with no other concerns.
It "worked." I got through the program, re-skilled, left the Army, at this point have quadrupled any salary I ever earned before getting into software.
But beyond that basic brutality of the experience of being mentally on at all waking hours on all days, and those waking hours often being well beyond 16, I ended up going through severe spinal degeneration in my mid 30s, obviously exacerbated if not outright caused by sitting too much, that ended in three surgeries in the span of 16 months, several years of intermittent disability and forced bed rest, cerebrospinal fluid leakage, an inability to walk without assistance for a while.
I ultimately got through it and seem to be basically okay in my mid 40s. Was it worth it, though? I have no idea. I'll certainly never do anything like that ever again. Physical health has become and will remain for the rest of my life my number one priority. I might deprioritize eating properly, sleeping enough, and consistently working out for a few weeks or even months here and there, but for years at a time? Never again. It's not just the severity of the experience itself. I'm not even sure the experience itself is all that bad. You get so high on the feeling of productivity and accomplishment that the difficulty of what you're doing barely even registers, and time flies when you're occupied nonstop. But I have no way of ever knowing how much it contributed to effectively losing half a decade of my life to a level of physical disability that doesn't normally happen to a person before they turn 70, during what was supposed to be the prime of my life.
It's possibly the reason I don't have kids. My wife at the time left me and by the time I remarried, I was in such bad shape that I couldn't even pick up my cats, didn't feel capable of raising a child when I couldn't even consistently get out of bed, and decided a vasectomy was a better option at that point. Again, I have no way of ever knowing if this would have happened anyway, but assuming the answer is even maybe no, was it worth to give up the chance of having kids to burn a little bit more brightly when I was 28? Fuck no, that isn't worth it.