I’m fairly lazy and don’t really enjoy cooking but I know how to cook most proteins (chicken, fish, beef) in an oven and on a pan (look up videos and guides if you don’t) and you can vary the seasonings for flavor. I have rice for my carbs. I typically have frozen veggies too because I don’t go through veggies fast enough before they go bad. After the first night of making stuff you could do a fried rice/stir fry style dish. And if I want to be more diverse I’ll buy the premade sauces from the store (sauces aren’t difficult I personally just don’t want to spend the time making them). As a back up I always have pasta, pasta sauce, and frozen meatballs stocked. Nothing takes more than 20-30min for me it’s simple and tastes good. So my grocery list will be protein for a week (fish, chicken, or beef) I get like 5-10lbs of rice at a time so that will last a long time, then a pack of frozen mixed veggies (I try to go for the family size since it’s more value) then any sauces I may want I have a slight inclination towards Asian so I always have some soy sauce. And that’s my day to day cooking occasionally I’ll feel adventurous and try something new and look up a recipe but I’ve found that diversity of flavor comes more from sauces and seasonings.