My day sounds very similar to yours OP, with 7 month old twins. Note my username
I kind of noticed they were getting hardly any daytime sleep and were grumpy, so have tried introducing more of a routine.
Unfortunately they will only nap for 30 minutes before waking up, 2 or 3 times per day... This is what I've been attempting:
7am Wake up, milk
Breakfast about an hour after that, then play with DH while I get ready for the day
9:30am Morning nap
11am Milk
12pm Lunch
I then put them down for another nap 2.5-3 hours after they woke from the first, so usually around 1pm. When they wake up from that, I give them another milk then playtime.
Around 5pm I give them some dinner followed by playtime. Milk then bed around 7pm.
As they sleep so little in the day, I've been trying to get them down for a third nap between 3 and 4pm but it's hit and miss whether they'll actually go to sleep. I'm not really sure how to make them sleep more...