I use my headphones in the office (can get noise cancelling ones but I find that normal over the ear headphones block enough sound). Or if someone is being loud on a teams call direct them to the area for such calls (people need reminding). If you don't have booths /pods etc for teams calls and proper "break out" spaces where people can go to talk suggest to leadership that the office is reconfigured so that there are decent places to take calls and have meetings, also creating quiet zones to allow people to work in the most productive environment for them.
I doubt your graduates are getting the best initiation into working life if WFH frequently. It's not so much that they do or don't want to be in the office as it is good for them to see and interact regularly and casually as well as on teams calls with people such as yourself.
At home firstly reduce in week activities and if you must keep up a punishing schedule then do it via school (music lessons, sport clubs etc) or at the weekend (my friends variously do swimming martial arts sports dance and drama school at weekends). With one 6 yo there can't be many activities at all. Maybe started swimming and rainbows but even that is unnecessary at 6.
There's 2 of you right? How much shopping cooking laundry and cleaning is that really? I don't mean to sound unsympathetic but I would have a much cleaner house and less cooking if there were only 2 of us.
Cleaner if you can afford it. Mine is ill ATM and my house is rarely clean all at the same time. It encourages you to keep the place tidy as well. Schedule them for Monday morning so you can Tidy up Sunday and then you're all out most of the week so you just keep on top of kitchen and bathroom for shiny clean house all week and only starts to get messed up by the weekend.
Cook and freeze so you always have home cooked meals but don't need effort on your WFO days. A shepherd's pie is 6 to 8 portions so make once, I'd eat twice during the week and then freeze in portions so that's another 1 or 2 meals sorted. Take out to defrost as you are on way out.
Other good freezer meals are curry (mix with lots of yoghurt for 6yo) soups chilli and bolognaise (cook rice/ pasta fresh).
I do a weekend roast or pie or something elaborate and then use up leftovers in the week. Roast chicken can be reheated with gravy for a fuss free roast mark 2 or sliced and put in wraps with salad and guacamole, my last scraps go in a sturdy fry or fried rice.
Does you 6yo take packed lunch? I make sarnies and freeze them (without salad!) Then I don't have to make every night. I also buy snacks that don't require making sandwiches such as sushi, mini hummus pots (or decant hummus into pots) but often I splurge on expensive and individually wrapped lunch things to make life easy. Like I buy the mini soreen but if I can't get them then I get a malt loaf, slice and butter it and rewrap each slice, put the lot in the fridge then put a slice a day in lunchbox.