We have a whole wall down the side of the playroom covered in Kallax. Half of them are filled with the tubs and the other half are shelves with boxes of board games and other boxed toys.
My kids are nearly 3 and 8 and to be fair most of the 8 years olds toys are in his room so it's just big toddler junk/millions of cars/bit of utter crap/figures etc/play food. I actually worked out the problem is they have too much and don't play with half of it!
I had a big weed through and for example worked out we had 20 dinosaurs so we now have 10 and the rest have gone to a better place. Ditto toy cars and play kitchen stuff. I worked out we had 4 plastic lettuces! No-one needs 4 of those! I started going in there with a big carrier bag once a month and removing anything for the charity shop/selling/bin and that has helped a lot.
Also anything with small pieces is in a storage tub high up so the 3 yo has to ask for it rather than just chuck stuff all on the floor then lose interest before I've noticed and made him pick it up.
As the older one grew out of stuff it goes up in the loft until younger one might be interested. If I bring it down and it's not holding his attention then it goes back up for a while.
We also have a small unit of toys in the front room which is more regularly tipped out on the floor used so I keep only big things in there or things with less pieces so it's easy for them to clear up at the end of the day without quite so much moaning.
Largely I've just accepted for the next few years until we are through our second round with playmobil etc that it's going to be a bit messy and when I'm really annoyed I try to remember that one day I'll miss the tiny dinosaurs and tipped out teddies.
I think basically letting go of caring so much has helped the most 