My 2nd grader generally spends 10-20 min on a math/ language arts worksheet, plus 20 min. of reading each night. I think that's fairly reasonable, but it's still like pulling teeth sometimes. I can only imagine what you're going through
I think kids need downtime outside of school, including time to have a hobby whether that be sports, music, etc. With all that homework, I don't see how that's possible!