I’ve tried so many things. At the moment I’ve bought several flexitubs and encourage the kids to put the toys in them and they can move the whole tub from room to room. It is seeming to work at the moment as the mess doesn’t seem as overwhelming for the kids

From my 4 kids only my boy is organised and neat. My youngest girls has Down syndrome and loves to throw. She can tidy, but only with supervision and a lot of structure. My other 2 girls are mess makers.
We do a reward once a week and I expect them to tidy their room at least once a week very well in order to get their reward. And we tidy the living area before dinner, by which everyone helps. Dinner doesn’t come on the table unless it’s tidied.

Getting children used to cleaning up after themselves is good for them and good for you.

I used to get my children to tidy up before I they go on the next stage, it was great when they were young but now they are 8 and 10, I had to introduce a new rule. no tv until 8am, but the room tidy, bed made and curtains opened before they can even touch the remote. even if its 8am and their room isn’t done, the remote can not be touched until its done. it works!
dirty clothes must be in washing basket after getting changed into clean clothes or pyjamas.
my son has a habit of waking up looking for clean uniform each day, I now get him to do it before bed time to avoid being late in the morning. if you ever find a dead insect or mice (in my case mice) under clean clothes that yet to be put away or room is untidy, showing them something can give them an idea if they want a dead spider or mice or some sort of insect in their messy room or clean clothes for next time. my husband has a habit of putting his clean clothes on the floor against the wall next to his bed. now he found a present yesterday a dead mice!. My husband can be a big kid too.

Storage boxes are a good way to keep rooms tidy.

We got some storage from Ikea – the frame and boxes. Makes it easier for them to pack away their toys. We also got rid of lots of clothes that were old, damaged or too small. We have hanging space so I got a 7 space hanging organiser and now I organise the kid’s clothes for the week in one go – you just put the clothes in each corresponding day and that’s it. So much easier!

also you can get your children’s clothes all hung up on hangers, if possible. saves folding time and the kids won’t dig through a whole pile of clothes to find that shirt they want. I t is all too easy to see what they want.

yeah i had a big clean up before christmas and we donated toys and that made a really big difference to getting things back under control. have storage options that allow them to see what they own vs digging through piles to find that toy. Encourage them to clean up and put toys away

Make a game of packing away too – fun can make a job easier.

Big colourful tubs for toys and all other bedroom items. Kids tidy before dinner – pack away toys and items.

Clean up as you go. When my daughter was little she had to take a game away before taking another one out of the closet. For years I helped her of course, but then it became an habit for her and she started doing it alone.

Depends how old/what kind of things, but in our house, my parents gave up trying for neat/put away properly, and just bought big bins/containers/washing hampers and every night we had the 5 min hurricane clean.
As mum was putting dinner on the table, she would shout go and everyone had to run around like crazy for 5 mins throwing everything into the bins/hampers (there were designated ones – clothes/soft toys/legos etc). In some way, I guess the frantic/being allowed to throw/slam dunk things into bins made it more of a game.

Can’t help you there – I believe children are inherently tidy and neat or not. Had 4 children, 3 neat and tidy and still are today, one even though he was in the forces for a few years and I though that would be great training, still leaves everything everywhere.
Wish you luck.