Has anyone tried saying screw it and cooking whatever they want for their toddlers?

I'm kind of at my wit's end with my three and four year old. They've become SO picky with food that they literally only eat carbs with some sort of sweetener (pancakes/oatmeal/cereal), cheese, hotdogs, pizza, and... that's basically it. Sometimes, with great cajoling, they will eat eggs, sausage, or beans. If I make a sandwich and it has anything other than cheese on it (i.e. lettuce, tomato, sometimes even turkey) it gets picked out.

I'm a single dad and I put vegetables and other kinds of meals in front of them, and they cry and scream and complain and don't eat. They sneak into my fridge or pantry when I'm not looking and produce some of what they want and eat that. They've figured out how to undo all of my childproofing (I've spent at least a hundred dollars on different childproofing stuff).

I see other culture's kids eating what is put in front of him. I watch the arabic children at a restaurant I go to downing lentils. I've watched my friend's kids eat a kale salad. Every week, I go to great lengths to plan out toddler meals and it seems like their behavior is only getting worse.

I'm close to saying f it and just making what I want to make and giving it to them. Don't like caesar salad? Too bad, that's what I've made. Don't like paninis? Spaghetti? Alfredo? You get the idea.

I know they will scream and cry at first but has anyone tried this to success? Do they ever just... give in?