OP,
Saying thanks is unbelievably basic.
That he doesn't shows he is both uncouth and disrespectful.
Stop cooking for him.
Be too busy with the children.
Sort your contraception out.
That he is so disrespectful of you is not good.
You will be returning to work thankfully, but him doing so little while you are on mat leave is setting yourself up for a tough return.
Stop doing everything.
Leave the cooking and his laundry to him.
Stop picking up after him.
Have you left both children with him for the day?
If not why not?
You are allowing your relationship to slip into resentment area which will destroy it.
Children learn at a young age to say thank you.
His refusal to say it is very rude but a very passive aggressive dismissal of what you do.
Don't underestimate his deliberate disrespect.
I would be telling him that considering his inability to do something as basic as say thank you, you will leave him to sort out his own meal.
He is tired?
How are things going to work when you return to work?
He's opting out of family life by being on his phone constantly.
Him doing so little and leaving a mess says so much about him.
He's a shit husband and a shit father.
You need to take an honest hard look at yourself as to why you havl allowed him to treat you like this?
Your relationship is doomed if you allow it to continue.
I hope you have family to support you.