He fucked up the drink, that's fair, maybe he didn't give it the attention he should have.
I wonder about some of the other stuff, though. As happens I considerably out earn my DH (and have a more stressful job) but if the situation was reversed I'd be really hurt if he felt the need to point out he was "the main breadwinner" when we both work, our roles happen to pay differently and by nature I'm more ambitious. He contributes as much of his income to our family as I do (all of it!).
It sounds like your DH is trying to support you in a way, he is also working, doing things with the DC, possibly finding it quite stressful seeing you stressed? He tried to find a practical solution by sitting down and going through the finances. He can't cook but bought food to make for you - you called it low effort but what did you want him to do? Learn to cook? Or try and fail?
What is the balance of other stuff like? The housework, the mental load? The DCs stuff? Does he try and take stress off you with these things or put more stress on you?
Practically, you've been through the finances and don't feel like there are options but burning out completely isn't an option either. You will end up quitting/ off sick / breakdown and your finances will be screwed anyway. There needs to be another option which might include changes for you both or all.
I know you are feeling alone and unsupported and that you aren't getting the care you need. Maybe you feel everything is on you? Because you have to stay in this job to keep the financial situation going? But I wonder if some of that is becoming resentment that DH doesn't earn enough to fix it? Even if he had got the drink right, would that really have been enough?
I could be hugely wrong and maybe he has been a shit DH and done a million tiny things to make you feel rubbish (or both could be true).
No matter what you do about DH though, something will have to give with work.