You’re in the trenches but it does get better.
Is there a way for either parent to finish work a bit early a few days a week so there is a bit more quality time on weekdays too. I remember those days where it was nursery, dinner, bath and bed and it’s not fun, thankfully I only had to do that a few days per week and worked shorter days the rest of the week.
Also if you can get yourself whatever home help you need, food shop deliveries, simple meal for kids and takeaway later for you as a treat, cleaners, ironing person, gardener, some high quality food prep / ready meals, whatever, just to allow you to focus on weekends as family.
I’d also suggest you and DH have alternative weekend mornings as a lie in, stick earplugs and an eye mask on and just get a few extra hours.
If you can also have the odd day where they go to nursery and you’ve got a days annual leave they don’t know about it makes a huge difference, I used to get all dressed as if I was going to work, take them to nursery and then go back to bed for a few hours with a movie and coffee - bliss every few months just to keep you sane as we had no babysitters on hand nearby. 😂
If they eat well at nursery then I’d speak to nursery about some recipe ideas as it’s clearly not a medical issues, it’s something that has become a habit at home, they may not actually be hungry if they are getting snacks. My kids had a few favourites from nursery lunches and I used to recreate them. If you know there are things they like then give that to them with new things to try on the side, eventually they might just try something. Clearing the junk out of the house is something we did after lockdown as we’d fallen into some bad heating habits. If they’re hungry it’s fruit, wee cracker, small bowl of popcorn etc., that way they’re hungry for meals and if you take them to the park etc. treats are okay.
It does get better, they’re just little. Sending strength!