It sounds like you've got a lot on your plate and I can completely understand why you are feeling resentful. It's unfair that you are doing absolutely everything. How old are your children? I think this makes a big difference!
I am a single mum but only have one child so have it easier than you. Here are my tips - the things that keep me from burning out.
Prioritise yourself. It doesn't mean you love your kids any less and it certainly doesn't make you a bad mother, quite the opposite. You need to be as physically rested as you can be and mentally well for your children. I go for a run and have a shower every morning, but it could be 10 mins of stretching, some yoga, body weights. I find that exercise gives me energy and I always start the day feeling like I'm going to conquer the day rather than think "fuck, here we go again!". When you have a positive mindset it's much easier to overcome hurdles.
Worrying about finances is draining and sucks the life out of you. I live on £450 month excluding rent/council tax/water/electric. That includes food, transport, toiletries, kids clubs, events, cleaning products etc... and that's in London. Sometimes I have a little left over at the end of the month. Good planning is important. I set myself a budgets for different things using Monzo so I can keep track over the month. You can almost certainly cut down on your food shop! I was spending a fortune on food until I really stripped back. You don't need to use every ingredient in the recipe. My weekday meals usually have no more thn 5 or 6 ingredients.
When it comes to cooking, I don't meal prep. I just don't have the time to do a big cookathon nor the freezer space. Instead we have the same meal two nights in a row. (Or for dinner then leftovers for lunch then next day). So one day cooking takes 20 mins and the next day 5 mins. On the 'less time cooking day' I use the extra time for a bit of cleaning. Eg. Bathroom or kitchen (basically the things that need a bit more of a deep clean).
Housework I do daily : dishes and wipes down kitchen in the evening, hoover the carpet in bedroom (takes 2 mins). Then when I get 5 mins it's easy jobs throughout the day as I see them, dust the bookshelf (it's always dusty!), clean the toilet, wipe the mirror etc. I don't get stressed about it, I try to follow the clean and tidy as you go rule. If your kids are old enough get them to help!! Even a 5 year old can be very useful
Again, I don't know how old your children are are but for me I have tried to steer DD towards independence even from very young. She is excellent at independent play because she has to be (I can leave her to babble and play with her toys for almost an hour just popping my head in occasionally). I don't want to sound preachy but I was adamant that she had to fit around my life rather than the other way round. (In reality everything does revolve around her... I suppose it's more of a balance). It's good for kids to be bored, that's when they get creative.
Give yourself a 'no commitment' day. A free day where you can just be. Whether that's an evening with no kids clubs or activities planned, a shorter work day, whatever but carve out some time in the week where you can just breathe and recharge.
Can you arrange lift shares? Again more info needed, but if you can take it in turns with another parent that can take some pressure off.
Getting the children to start helping with small tasks such as putting their school uniforms in the washing, putting their own clothes away, packing their school bags, helping with tasks such as laying the table, putting toys away, dusting (I am always dusting because we live in a city flat!), hoovering. It's doesn't have to be a punishment! Make It fun. Stick on some music and let them dance around 'helping you clean' - you will be able to actually do some housework and it will also be good for them.
I used to look after 3 boys (full time for a while whilst their mother was in NZ). I used to dread those winter school runs (35 mins each way). The only way we got through was solidarity, trying to make the drives fun. Music helped using the time to have a chat, or play games. Making sure that everything is ready before takes the stress away. There is nothing wrong with having toast on the way to school if you are in a rush. (It's one of my happy childhood memories, eating toast whilst walking to school).
No screens in our house. My DD is still to young to care. But even when I was looking after the older kids it was also screen-free. I found that the kids were more involved in the household, wanted to talk and help. In my view when they have a lot of time on screens, kids become detached, grumpy, don't enjoy family time as much because they are restless to get back to whatever they are doing. It's just not a nice dynamic. I think it's important to enjoy your time with the kids rather than feeling as though everything is on you. For a mental shift try turning all your 'have tos' into 'get tos'. (It really works!) Practicing gratitude is a great way to curb resentment in my experience
Do you have friends with children a similar age. Can you do family play dates? Ie. Mum and kids come to yours, you two have a coffee and chat while kids play outside sort of vibe, and then switch. Then you can have some adult time and kids are happy together. It's important that you have adult relationships, so you can talk about stuff, normalise the everyday challenges of parenthood.
Finally, I take a moment when I feel stress bubbling up inside me and ask myself "how important is this?" Will the world end tomorrow if it doesn't get done?" (Of course not!) Why am I stressed? (Overwhelm usually) Will something terrible happen if this is not done now? (No, most things can wait) Would I rather be happy and calm and enjoying my day? (Yes) Only give things the amount of time and attention they need. Ask yourself, is this a 5 minute task, a 10 minutes task or is this a 'i need to sit down and concentrate on this for an extended period of time kind of task".
I have a to do list on your phone. So if I get a spare moment and don't know where to begin I can start working through the list. At the top of the list I have my daily task (is. The one thing that MUST be done) as long as that one thing gets crossed off, I can go to bed happy.
This is just my experience. I hope it helps in a small way. You sound like a great mum.