For my kids 7th grade takes about 2.5-3 hours of what I call “seat work” where they are sitting and doing school at a desk (or reading on the couch specific subjects independently or as a family), then add in other tasks that go towards learning, but are not necessarily sitting at a desk for work, for example music practice.
I grew up being homeschooled and even in highschool my schoolwork took 3-4 hours/day. When you can have focused time for work with out distractions it can be very productive. It is one of the many reasons I really like HSing, it allows extra time to enjoy hobbies, time to visit with friends, and when I was old enough time to have a part time job and still visit with friends. 🙂