You as a human could also live with the same food every day if it covered every dietary need. Especially if you depended on someone else to acquire it and had no choice.

There is an evolutionary push for a rich variety of nutrients obtained from a variety of sources, but the mechanism driving that daily “need” for variety is force of habit and desire for novelty. On top of that, some people are happy to eat nothing but junk and have very narrow tastes. How come?

Also, I can assure you, a lot of cats will periodically stop eating a certain brand or flavor and go through cycles. Does it mean the food isn’t really covering their needs or are they just bored of the same flavor every day? Hard to know, but I would argue your assumption about humans being too different from their pets when it comes to variety in their menu.

I don’t think it would cause any problems. I’ve taken iron supplements of 1000 mg and had MRIs done and nobody ever gave me a warning about anything wrong with it. Surely iron in even lower and more distributed amounts does nothing too.

“know thyself”

Plato? I think it’s Plato idk