Unfortunately there isn't a lot you can do about that lunchtime to naptime phase as for sure it is the most exhausting part of the day. One of the reasons we deserve our break during naptime.

Can you have the kids clean up the play area before heading outside if they aren't playing in it once they come in. Then once in they do things in the kitchen while you make lunch. I tend to do diapers before lunch and then just a quick check before going down for nap as mostly they are fine which saves a ton of time and only the potty trained kids need to be dealt with.

I skip all foods that require me for anyone but the babies such as yogurt or spaghetti or applesauce. I serve mostly finger foods and can have some of the work predone such as cheese already cubed. Not having to deal with messy foods or feeding kids frees me up to deal with the kitchen. While they eat I unload the dishwasher from the night before and start reloading. But you might find you could actually get the pots and pans washed up and stuff from morning snack. Then once kids are down just have the lunch cups and plates to do or even leave them to do with supper but at least your pots and pans needed to cook supper will be clean.