"Startup, parenting, hobbies, friends. I think you can do 2 of these well. But you'll have to quite light on the others."
Someone on X, don't recall who, but it resonated.
It shouldn't be hard though. For me personally, I'm mostly friends with other dads with kids and I do my hobbies (music, rock climbing, skiing) with my kids. It's not that difficult.
For “parenting” and “startup”, I would say that each is extremely hard to do well even when it’s the only thing on the list.