It is tough some times I really get that - I have 5 kids too & I am on my own.
As the others said you do need to let go of some stuff.
What helps me is this: I cook all the meals for the week on a Monday - so for 4 hours I cook (obviously with loads of interruptions!). So then I know that all the meals are healthy, taken care of and it's all organised. This saves money as I meal plan.
Each child is responsible for their own room and another room in the house. There is no TV no computer access until this is done. That's it not negotiable.
Meal times everyone puts their own plate in the dishwasher. One child wipes the table and placemats. One child packs the dishwasher (pans etc) and the other does the benches.
I vacuum the house after dinner so that it's all done for the next day.
DD6 job is to put the bath toys in the basket and take the dirty clothes to the laundry - she also feeds Pat (cat) & Gloria (house dog)
She has to make her bed in the morning and keep it tidy.

DD7 unpacks the dishwasher in the morning and makes her bed.
she sets the table at night
she cleans up the loungeroom before dinner

DS9 he unpacks the dishwasher in the afternoon
packs it at night
feeds Doug (outside dog)
takes out the garbage bins to the road once a week and washes out the inside bins
keeps his room tidy
helps to clean off the bench in the mornings.

All 3 put their lunch boxes in the dish washer when we get home from school and they all help me to pack the lunches. Its' a team job.

So, that's what I do but it's different for all families. My kids get pocket money if they do their jobs with kindness - for me this means not whinging, not complaining and helping each other when required. As I said - no jobs done or a messy room and it's no tv or computer for 24 hours...

They all put their folding away sometimes (often I do it whilst they are at school) & sometimes we all sit down and one folds the undies, one pairs the socks etc etc.

It works here - I hope you can find an answer for your family...