I have three with one on the way. It’s a constant struggle to keep the place livable. Before I had children I was not a neat person and kept things livable by not doing things that made mess and staying out as much as possible. Can’t do that with kids, so what’s the trick?
Best rule is to tell them toys that are left out are in timeout for a predetermined amount of time. Not necessarily forever. But not necessarily not forever if it continues to be a problem. Have a place for things that everyone is aware of and have them work together to do a sweep every night or morning before the games begin.
This way there is cooperation and accountabillity. Do not give in when it has to be enforced