Sometimes, when thi gs are bad, they have to get worse to get better, and by that I mean the mess.
So even though you're doing things you don't see any benefit. But it's still worth doing the jobs. Strip the beds and spend the day over the washing machine. Get it all washed and dried and away. Ignore everything else. While you're waiting for a load to finish, wash up and dry up.
And that's probably enough for one day.
Day 2 tackle the kids bedroom. Take a bowl of hot soapy water and a bin bag uo with you. Clear the clutter out, wipe the surfaces, open the windows and finish the job. Of you find washing, get it straight in the machine. Wash up and dry up again. And that's probably enough for day 2.
And repeat for each room. Over the course of a week, you'll be knackered but it will be done.
Things I find help are seeing jobs through. So, get the washing away when it's done. Dry up after you've washed up. Even if you need a cup of tea between washing up and drying up, make sure that the drying up is done.
And then to keep on top of it, make the beds as soon as you're out of them. Do a load of laundry first thing every day. Before you come down stairs bring anything that doesn't belong down with you and pit it where it does belong. As you leave a room have a look round to see of you could do a 2 minute tidy round.
It sounds very difficult for you, I hope you find a way through it.