[PerfectElement]

I'm a solo-founder too and I agree that cognitive load is the biggest problem, even working less than 40 hours/week.

I've been on this for 4 years and I feel like my personality has changed due to the fact that my brain can't dedicate reasonable resources to anything other than running the business. I used to have several interests (musical instruments, travel, film, photography) and now I can only afford to care about business and family. The only things I can talk about are related to business or child-rearing.

What keeps me going is that I should be able to retire at least 20 years sooner than I would by working a regular 9 to 5 job, so I'll have plenty of time to dedicate to other interests.