https://www.budgetbytes.com/ has a lot of cheap and wholesome dishes that should be easy enough for everyone to follow.
https://www.themediterraneandish.com/ also has a lot of wholesome dishes.
https://www.justonecookbook.com/ if you're into japanese flavours but you're willing to avoid americanised asian foods.
Stay away from processed foods, like deli meats and "cheese" products.
Use ingredients that you can cook from scratch, not a can of "cream of mushroom" or some other bullshit """american""" cooking.
Eat fresh fruit and vegetables.
If you're autistic and can't stomach things like salad, you don't need to make salad out of bullshit iceberg lettuce but you can make it from fresh spinach or a cabbage you like.
There are mildly healthier options when it comes to things like salad dressings and vegetable sauces like tzatziki or a tahini dressing.
Don't be afraid of fatty foods like fatty fish or nuts. A handful of almonds is calorie dense, yes, but the oils are super good for you.
Cooking smarter is cooking healthier, IMHO. You're allowed to treat yourself on occasion, not every day. Learn to love a platter of fresh fruit and veggies that you've cut into pieces. Eat what's in season.
garlic powder and onion powder
Powdered flavourings are fine but I would look at the ingredient list to make sure it's not full of any additives that don't need to be there. Fresh garlic and onion isn't difficult to prepare, just remember to use your kitchen ventilation while you cook, onion smell clings like a motherfucker to your clothes in my experience.
If your eyes get runny while you prep onion, throw that bitch in some cold water for a couple of minutes after you've peeled and halved it. You can dump the water and give it a second rinse if you prefer, and it won't make the onion taste watery.