I don’t think you read my post carefully. I said humans have teeth for both meat and plants. I didn’t say that humans aren’t omnivores. I just said (implicitly) that they are not obligate omnivores.

Proteins are not a concern, you can get all essential amino acids through only plant protein. Pretty much the only one that is hard to get enough of is B12. With real determination it can be done but it’s easier to just supplement. By the way, most omnis also do not get enough B12 and eat supplements either directly or through fortified foods. It’s just usually they are getting it through fortified milk which vegans don’t drink.