My simple answer to substitution is to just eat something else and not look for a substitute.
Most of these substitutes are just substrates made out of whatever can pass as similar and with "added vitamins" to check boxes, a lot of which don't even end up properly working like the vitamin in the form as it is in the original object. And this is on top of the manufacturing costs of the ultra-processed foods which seem low because of how normal food prices have been inflated.

There is a huge variety of diets that has historically worked for people and any can be chosen or even mixed and matched to complete dietary requirements.
For instance, you don't need dairy with your bread. Just make good quality pulses and beans with gravy (can be eaten with rice) and use some of the remaining gravy to make your bread tasty or just have bread with those pulses. Quite a few of the remaining nutrients can be obtained from accompanying salads and fruits. On top of that, fruits contain many more components (often lost when processed) whose effects have not yet been properly appreciated and quantified, making it hard to give them as supplements.

For some remaining nutrients unavailable as components of vegetable food, historically, people used fasting. Although this depends upon the specific gut microbiome and whether fasting will cause the specific nutrients to be produced, so I guess this cannot be lightly recommended across geo-cultur-racial boundaries. (Now of course, if some rich people really wanted to help with this, someone could come up with some probiotic drink that permanently enabled people generate those nutrients on fasting)