First off, I’d make everyone really muck in with the house. Write a list of what needs to be done. Sit down all together and agree who will do what. 9 and 6 year old are both old enough to run a hoover round and pick up after themselves. Even three year old can ‘help’, put their dirty clothes in laundry, make bed etc. Emphasise that you are a team. It is not YOUR job to be a servant.
Be honest and say it is getting too much for you. Encourage the children to sort through their stuff and get rid of things they don’t want anymore. If they sell it on eBay they can keep the money etc.
Ask them what they want to do for a day. Have a day each where they can each choose exactly what to do. We have had some lovely simple pleasures like this. A midnight feast went down very well and DC often ask to do it again.
Food wise, again, get them on board. Ask them to come up with some ideas, from books or internet if they can’t think of anything. Ideally things they can help make. My 8 yo can make carbonara start to finish apart from draining boiling water for example. Have a themed day, if DC are studying Greece try and make some Greek food for example. It doesn’t need to be complicated or expensive.
The thing I have found with DC is that time spent together when really focussed on each other, no devices, is really valued by all of us.
We like ‘reading days’ when we all get blankets/picnic rugs depending on time of year, then curl up with our own books and lots of snacks, just together.
We have also got into board games.