Like you don't even have to know all that much and the bar is crazy low. Even if your diet is absolute garbage it's unlikely you're actually deficient in anything.
I've just been accumulating daily supplements from dr recommendations over the
years — the good fish oil for my dry eyes, b12 because I don't eat much meat, high-dose turmeric because mild jaw inflammation, d3 because I'm light sensitive and don't go out in the sun enough, and a women's multivitamin.
I don't really think about my diet at all outside of roughly total calories and haven't gotten a bad bloodwork yet.