As an adult, you develop the agency to force yourself to do things you don't like doing

I can tell you as someone who was never forced into any extracurricular activities and was forced to go to church-schools that you probably should force your kids to learn something well (and not send them to religious schools)

You are not forced. You do stuffs you dont like because you racionally evaluate consequences that could probably not worth it if you don't do it. Why cannot we approach same attitude when raising kids?

I spend at least 40 hr a week doing something I have no motivation for. Most people do. Even if you don't hate your job, would you actually do it if you weren't getting paid?

Do you find it healthy? Doing stuffs that you hate? Isn't that a consequence of forced education system?

Healthy in what sense? I wouldn't describe my job as "healthy activity". But I also wouldn't describe it as "unhealthy" and it enables me to enjoy a higher quality of life.

Nobody's forcing me to work. I could quit today if I wanted. But I doubt that would be beneficial to my overall health, given I do not have the wealth required to support myself and my family for very long.