Ok, this is going to be long!

I would advice, apart from tying out new recipes, try to look at how you cook rice, make a green salad and tomato based sauce again. Often there are a few basic things one can improve that elevate all other dishes as well. This doesn't have to be expensive, you save a lot of money by not buying the meat, after all.

(A few of these things you will probably know, but perhaps you learn something new.)

For rice try the following:

• most children prefer basmati rice and rice with tumeric
• cumin also tastes good in rice but not all kids like it
• most types of rice have to be rinsed a few times, a good job for kids lol
• when you let the rice soak in water (~30 min) after rinsing it, you get more predictable results
• when you want to fry the rice, use rice you cooked the day before
• try different rice varieties from different brands because they all tend to need a different amount of water for best results
• when your family really becomes rice fans invest in a good rice cooker because it saves time and older kids can make their own
• after cooking, let it steam for a few minutes on the turned-off stove

For a good tomato sauce try the following:

• diced or crushed tomatoes in cans often have low quality, when using cans use whole peeled tomatoes and cut them when still in the can
• do not crush garlic, instead chop it very fine
• use a really good oil, it has to taste so good, you would eat it with bread with nothing else
• oil is a whole beast, try different types and be careful which of those can be heated to which temperature
• some finely chopped celery often tastes good in tomato sauce
• heat very slowly and don't make it boil, don't cook too long
• add sugar to taste, baking soda if it is too acidic
• add herbs only when the sauce is finished, perhaps add oil again
• some people think tomato sauce tastes better the next day

Some tips to make your salad better:

• the oil hint from above
• for vinegar all the hints for oils apply
• mix something crunchy into your salad, many kids love sunflower seeds or peanuts, which are less expensive than walnuts and similar
• when you want roasted sunflower seeds, buy them raw and roast them shortly without oil in the pan until you can smell them
• wheat grains roasted taste great, they smell amazing as well
• top your salad with something hot, for example caramelized pear slices or seasoned tofu cubes, marinated fried champignons, etc.
• get a salad spinner if you don't have one already
• some children like vegetables raw they do not eat cooked, for example fine broccoli florets and zucchini slices
• good mustard or lemon juice on the side

General tips for vegan and vegetarian recipes:

• a good rule when it has to go fast is: combine grain + green + bean
• experiment a lot with combinations of textures
• grating vegetables adds lots of moisture, can be good or bad...
• roast whole spices without oil until their smells hit you before you cut them and put them into your dishes
• make your own vegetable broth by freezing clean vegetable scraps (skins and ends) and simmer them when you have a bag full
• maple syrup + non-dairy milk mixed make a crust on baked goods
• infuse oil yourself with herbs, chilli, garlic
• learn to sauté a base of spices, garlic and onions before adding your ingredient
• learn how to make natto, get used to the taste and then addicted to it
• now that you are a pro with herbs, make your own fresh tea and experience a new world of taste

Ingredients which you perhaps never used before but are very useful:

• nutritional yeast !!
• soak and blend cashews for a versatile cream base
• Kala Namak
• liquid smoke
• miso
• tamari
• seaweed
• the water from chickpea cans is aquafaba