It's interesting, I have found in my life that periods when I've had more time available I have been at my most disorganised. When I'm on a tighter schedule everything else becomes more structured.
I don't know whether it's because when I'm busy I know I can't put anything off, I just have to get on with it? Or whether the busier activities give me a structure that I can build other things around. e.g. my library books need to be returned - if I'm not busy I just have it on my list for the whole of the week. If I'm on a tight schedule I can spot an opportunity on Wednesday afternoon when I'll be passing the library so i schedule it in for then. There's also something about urgency... If scheduling the car's MOT is something I can do anytime in the next 3 months I feel no urgency, so it remains on my to-do-list and I just feel the burden of it being always on my list. If it needs done next week, I do it.
If you look at your current daily schedule, is there a fixed time when you can make the beds (e.g. as soon as you return from taking dc1 to school), kids reading - maybe in the 15 minutes somewhere between teatime and bedtime. Can you have one 3 minute tidying blast (involving dc) and another 3 minute blast as soon as they go to bed - that means before you do anything else. It is amazing how much you can get done if you put a timer on.
If you look at your weekly schedule are the fixed days and points when you could clean and stock the fridge, clear the car? e.g. one of the days when you've dropped dc2 at nursery you immediately deal with the fridge, another day you immediately deal with the car, another day you arrange to kick back and meet you friends for coffee, or schedule future playdates, or plan dates nights with dh (i.e. all the nice stuff).
Is there one morning (or day if dc2 does to nursery for a full day) every month that you can commit to 'big admin'. Check the timings for dog insurance, car admin, pay the bills, schedule dinner parties.
I know that sounds quite structured but if you don't have the structure of working hours then using the structure of you other activities can be a good starting point. Once you get into the swing of it, it soon becomes an easy habit.
Re your own eating - do you make a weekly meal plan? even a rough one that's open to change? You say your dc eat good meals are there things you can swap up to make those more adult friendly e.g. they eat fing fingers and veg, you eat salmon and veg. They have sausages and veg, you have roast duck and veg. Always make an extra portion that you can have for lunch another day. (sliced salmon and salad; shredded duck and salad).
If your dh is working long hours then most on the above is on you, but holiday plans should be about both of you. Make one of your date nights about the next couple of holidays, get a shared agenda then fix the research, planning, booking somewhere into your next week's activities.
There's also a lot about you, how you like to do things, what you enjoy, what makes you feel satisfied. Also how you like to process information. Do you work best with paper lists that you can visualise, or do you like digital reminders on your phone? Do you like to do any of the domestic activities - cooking, gardening, flower arranging, crafts, DIY? If you prioritised them would it help you fit other tasks around it? Do you have other beautiful passions - playing music, drawing, writing? Where do you fit those in.
@Embarrassinglyuseless although you seem to have a fortunate live, you don't sound like you are doing enough that really makes you happy, that thrills you and gives you joy (family and children of course). Find that, and find how you can fit your domestic responsibilities around it.