I never think about my diet, mostly eat beans and rice, random stir fries, dhals and burritos and oats . Only supplement b12. In my 30s, perfect levels across the board and am a distance runner. Actually I had to stop supplementing b12 as it was too high for a while (many foods are enriched).
You are spreading misinformation. There’s massive amounts of iron, protein, and calcium in random veggies and lentils. Vitamin D you get from being outside like everyone else.