How can I keep a balanced diet when there are so many different vitamins, minerals, proteins, fats, carbs, etc?

I’m having a hard time wrapping my head around how people have all these different diets, but they can’t all possibly include absolutely everything you should have in a meal, could they? We could start with minerals just to get a general scope for how many of one of these topics you need. Magnesium, calcium, phosphorus, sulfur, sodium, potassium, and chloride seem to be the main ones. How is someone supposed to get all of those all of the time without going over on some, short on others, or not getting one of them at all? These are just the minerals, though. I’m not educated in this matter in the slightest, but still wish for a somewhat in-depth description of why or why not you wouldn’t need certain nutrients. Also, this is a shot in the dark, but is there one meal you can eat 3 times a day that has everything that the body needs to simplify this process? I know that body type and gender must factor into this somehow, so that I would be appreciative if anyone could explain that as well. Water was another thing I was curious about. How much water is too much water? Anyway, this sounds like a rant now, so I guess I’ll just let reddit do its thing.

How can I keep a balanced diet when there are so many different vitamins, minerals, proteins, fats, carbs, etc?