Bolognese & stews don't need to be simmered for long. They just need to stay hot for a length of time. So I turn off the gas within a couple of minutes of them simmering and leave the pan on the hob with a lid on tight. By the time the pan has cooled, the food is cooked. Then I just give it a blast of heat to warm through and it's ready.
I always cook mince, tinned tomatoes and onions in a large batch then divide it up into chilli, Bolognese and cottage pie filling. Similar with chicken - make it into casseroles, curries and pie filling with the same base (stock cube in this case instead of tinned tomatoes) . Add the relevant herbs and spice, stir in, pop the lids on to carry on cooking in their own heat so the spices develop and freeze.
If I'm making mash I do loads and freeze the extra. Not great to eat on it's own, as a side dish, as it can be a bit watery but you can use it to top a cottage/shepherds pie or put into fish cakes. I only cook mash for cottage pie etc if I'm making it as a side dish. So the mince may be made and frozen today but the mash may be batch made next week and frozen as that's when I'm planning mash for dinner. Then defrost and put it together when you want it. Defrosted mash is great for bubble and squeak too - just add left over veg (doesn't have to be 'green') and fry it up with loads of salt and pepper and Worcester sauce.
I also use up salad leaves that are going a bit limp by adding them to curries or stir fries. They're exactly the same as spinach or any other leaf veg so they wilt down and add colour and bulk. Better than binning it.
And if you have things like Tesco clubcard vouchers, keep a check on what you can use them for. At the moment, for example, you can use clubcard vouchers to pay for Disney plus, Cineworld, use them to buy English Heritage membership as well as the usual vouchers for restaurants. Our local supermarket is Tesco (Lidl etc is over 15 miles away) and we have their credit card as we may as well get maximum clubcard points on everything.
Check the terms on days out tickets to zoos etc. Some places allow you to make a day ticket into an annual one for nothing. Even if you don't think you'll go back, 'annualise' them. It costs nothing and it's another place to go for a day out again if you find yourself in the area.
Ring places like AA or telephone companies and ask for the retention people. You'll often be offered a deal if you threaten to leave.