I teach kids this age.
From a teacher's perspective, all the advice here is good. And I'll bet you've probably tried most, if not all, of it.
Definitely talk to the teacher. My guess is that it would be unusual for someone 6 to need homework every day unless there is a problem.
If the child is struggling, negotiate with the teacher a reasonable amount to be done. Sometimes kids will work if the load is reduced. If the child is facing the possibility of repeating a year, the family should decide if that's in the child's best intersest. (I work in a jurisdicition where that almost never happens, but if it's a possiblity where you live, find out what the situation is.)
You'll also have to figure out if the child needs academic help or an attitude adjustment. The teacher will have a take on that. Some kids, especially kids who are the youngest in a family, find it a jolt to be expected to be responsible for their own learning and put up quite a fight. Secretly, they do want to be competent, but they are afraid they'll lose their special place in the family -- that of being waited on hand and foot.
A poll such as this can only give you suggestions. The family and school involved need to work together in the best interest of the child.
Best wishes.