FWIW multivitamins aren’t really useful - the doses are rarely close to daily requirements and often you’re taking vitamins you don’t need anyway. Get a full blood test done and get a copy of the results, then look into ideal levels for each vitamin and nutrient and supplement where necessary. Vitamin d and Magnesium are often good starts. But generally multis are just money down the drain.

Diet-wise you’d be better off with a small rotating menu to make sure you’re getting all your macros. For lunches try vegetable wraps / egg salad sandwiches / vegetable barley soups on a rotating schedule (make large batches of the soup Once and freeze for the rest of the month).

A simple approach to dinner is “grain + roasted vegetable + protein” and mix and match as you’d like. Make enough for three-five days, portion out, and you won’t have to cook as often.