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?
Like everyone is saying here, for literal cleaning (mopping, toilets, dusting, baseboards, etc.) GET HELP if you can possibly afford it, your unpaid job is mom, you can’t add cleaning person to that.
For straightening get bins and give up on organizing. A bin for each kid in living room for whatever, clean clothes bin and dirty clothes bin for each kid in bedrooms, teach your kids to do laundry (my mom said anyone who can reach the knobs on the washer with a stool can learn).
Like you, I struggle with organizing and cleaning. The only way I can keep things neat is by not owning much, and yes when you have more people not much x5 or x6 is still much.
Realize nobody will judge you for a kinda messy house when you have little kids, or if they do they are delusional assholes or have wrong priorities. Neat house is not a priority, kids are.