I think you just gradually get into a routine, especially as they get a bit older and can be more relied upon to sleep/eat at set times.
My day looks something like this
Get up,wash, dress, makeup, brush hair, make beds, open curtains, sort out load of washing, get baby and 3yo dressed -baby plays with toys on my bedroom floor (or follows me around whinging a bit depending on his mood)
Take baby and load of washing down, put baby in high chair with breakfast. Get 3yo breakfast. Shovel in own breakfast, empty dishwasher and reload with breakfast stuff, put washing in machine, put washing from day before in tumble dryer if it’s not dry, wipe baby and high chair, sweep up around table, wave off older two dc, finish getting 3yo ready
Leave house 8.30 on preschool days, 8.45 on other days. Either toddler group or soft play/farm/park/just running errands.
Use baby’s nap to clean house and hang up washing
Make, eat and clear up from lunch.
Play with baby (and 3yo when she’s there)
Use baby’s second nap to do any admin/more housework/meal prep or just play with 3yo
Evenings I make packed lunches, cook dinner, tidy up from dinner, tidy up toys, bath baby and 3yo, get them to bed, shower, clear up anything else that needs doing, sit down by 8.30.
I’m not working at the moment but when I am my mornings and evenings look much the same, I just add a little bit of housework onto the evening (15/20 mins) and do more at weekends.
I wouldn’t say I am ever on top of things but we’re all washed and fed, the house is passable and I’m semi passable so that will have to do!