Consider investing in a couple of food flasks. It expands the number of lunch options no end. Every time you cook something suitable for reheating and that goes well in the flask, make double and freeze the extra in individual or double (for you and ds) portions. Then defrost over night in the fridge then microwave in the morning and put in the (preheated with boiling water) food flask. Wet foods are ideal curries, stews, chillis, pasta with sauce etc, soups. If you need to add a carb, I usually use something bread based. So curry you could add chipati for example.
Otherwise cold options
Ploughman's bread, cheese, apple, pickles etc
Cheese and crackers
Tuna pasta salad
Moroccan cous cous salad
Mexican bean salad.
Chicken and bacon salad
Fritata
Pita with falafel and salad
Any kind of bread, wraps, baguettes, bagels, pita etc with filling eg. Cheddar cheese with salad and chutney, Brie and cranberry sauce, blt, tuna with peppers and sweetcorn, houmous with grated carrot, ham and tomato, cream cheese and cucumber, egg and watercress
Then fruit, veg (with dip if you want it hummus, guacamole, cream cheese).
Add additional snack items if required.