It might be a little easier to make a bento that starts when you start work. Introducing "Orusand", an epoch-making bento goods that allows you to make sandwiches with just one piece of bread.
Orusand is a thin polypropylene sandwich case. You can make a sandwich that is folded in half by putting a piece of bread that is cut into 6 or 8 pieces and ingredients such as eggs and ham (8 pieces are recommended for ease of making and eating).
It is also a point that your hands will not get dirty easily if you take it out from the side when eating. Normally, you can make one type of sandwich with two pieces of bread, but you can make one type with one piece, so you can enjoy a wide variety of sandwiches. However, since it is not completely sealed, it may be better to avoid ingredients with a lot of water.
When you finish eating, you can fold it compactly, take it home, wash it and use it repeatedly (dishwasher cannot be used). In addition to lunch boxes, it seems to be useful for making breakfast and snacks.
If you want to make a sandwich with a beautiful cross section, it's a different story, but Orusand seems to be useful when you want to make a short-time lunch with the ingredients at home. I bought it at Tokyu Hands, and the price was 735 yen (tax included) for 3 pieces.