I could have written your post ten years ago! I had four children aged 5 and under, DH away in the forces..and kids who just wanted chicken nuggets and chips!
They didn't die of malnutrition and they aren't still eating chicken nuggets either :):)
I gradually gained confidence in cooking basic meals (I still don't do cooking for pleasure...I'm just not interested enough!).. and had a basic bunch of reasonably healthy meals..
It used to go something like :
Sunday.. roast chicken, potatoes, carrots, parsnips (disguised as potatoes)
Monday... beans on toast
tuesday Pasta and bolognaise sauce..(bought) but threw in sime fine chopped veg
Wed ; Jacket potatoes.. choice of cheese, tuna, coleslaw
Thurs; curry with rice (usually chicken) chuck in some sweetcorn, onions...
Friday.. chips!!!
It still DOES go pretty much like this.. but the roasts have become varied, and even DS1 now happily eats just about any roasted veg.. beetroots, sweet potato broccoli etc.
I batch cook a huge vat of spag bol (again..lots of veg thrown in) freeze it.
I'm never going to be pouring over a cookbook.. I just am not interested, but the children are older teenagers now and all have grown up strong, healthy, and unlike me, three of them enjoy cooking!!!
Snacks became grapes, raspberries ( shove a small grape inside a raspberry and eat.. fun for the kids to do!) and random fruit.
- we did have a 4 year long phase of DS1 eating an awful lot of pot noodles but that's normal teen stuff and I made sure he drank gallons of milk and orange juice
I'd ditch the puddings tbh.. no need.. 'if you are still hungry here's the fruit bowl' OR raw veg bowl. I don't like fruit very much..never have, but love raw carrots, cauliflower, fresh cooked beetroot etc the my lot have taken after me and are often found scrunching through a bag of salad or a ton of baby tomatoes!
it IS tough when you are alone and doing it all.. and you should not be so hard on yourself.. just make easy changes..small ones...