Focus on your kids, your health, and your work? It seems like a very tall order.
You've studied many notable builders, but have you studied the great dads? How much time does one have to spend to be a great dad? Do they get to pick the times when they can spend their focus on being dad, or do they have to be present at times they'd rather be doing other things? I think being a great dad might involve a lot of taking your children to sports practice, music lessons, play dates, libraries, and tons of other activities until you discover what clicks with them, and then there's many years of supporting those interests. I don't think you can just put it on pause during the week. To be a great and present dad, I think you can only count on being able to spend maybe 55 to 60 hours a week on work (with a lot of that being after bedtime and/or starting very early).
Looking at the great builders, I think the common element is that they picked the right thing to work on at the right time, in the right place, executed better than their peers, and also had a ton of luck.
* Zuckerberg was in the right place at the right time with ample luck and he chose to drop out of Harvard to spend a few years doing the hardcore startup house thing working exclusively on building Facebook, and nine years later he had his first kid. Right place, right time, strong execution, and much luck.
* Bill Gates was in the right place (a high school where he got extensive access to a mainframe computer, then in a local company that gave him and his friends unlimited computing time in exchange for them finding and fixing bugs) at the right time (when mainframe computers were an extremely rare and expensive thing and before operating systems existed) and he dropped out of Harvard to go all in on building Microsoft, then 21 years later he had his first kid. Right place, right time, right skills, great execution, and much luck.
* Paul Graham was in the right place (a Harvard CS Ph.D. who studied design at RISD living in NYC) at the right time (during the Internet 1.0 boom and before both the bust and before anyone else had brought a site building cloud application SAAS offering to the market), and he brought a great idea to market in time to sell it to Yahoo in 1998 for $49M of stock and he correctly elected to cash out his stock before the bubble burst in March 2000. And then he leveraged his great technical and business faculties to identify and develop great business ideas via YCombinator (2005-present). Then he had his first kid in 2009). Right place, right time, right skills, great execution of a novel great idea, and much luck.
* John Carmack is probably the platonic ideal of focusing and getting things done. His work ethic and habits are legendary (8 hours of sleep a night, 10 hours of focused work a day, and 60 hours of work a week) as is his output (Doom, Commander Keen, Wolfenstein 3D, Quake). In 1978 he discovered video games and in 1982 (at age 12), his family bought an Apple II computer and he quickly learned BASIC to start making games before digging deeper to learn assembly code. He gained deep and extensive knowledge of how computers work, motivated by his drive to make games, and this enabled him to make the limited PC hardware of the time do things comparable to purpose-built arcade machines. He came up at the right time, had sufficient interest, drive, and vision that motivated him to deeply explore and master computing as well as design and develop many iconic games of the 1990s. Then in 2004 he had his first kid, at which point he started working less, although still a 50+ hour per week workload. Luckily his children are interested in programming, which makes it easier for him to get quality time in. Still, right time, great skills, great ideas, much luck.
* etc.
Having a child already, you might be a bit constrained. But if you can manage getting into the right place to seize upon a great and novel idea that you are uniquely positioned to execute on, you might be able to build the idea out while the market and need is unserved.
Another potential strategy is to work on an established business model that someone else came up with, and spend your evenings and weekends with your children. The best dad I knew growing up did this (he was/is a database administrator and was the dad of three of my friends I knew through my boy scout troop who have all grown up to do incredible things and also be deeply happy people) and is still one of the coolest, most interesting and well-rounded people I've ever met.