This article by PNAS does not seem to support some of what you said.
https://www.pnas.org/doi/full/10.1073/pnas.2115540119
Humans can and do thrive on a vegan diet. I’ve been one for over 15 years including my time in the army. I’m not on medications. I take algae pills for omegas. I hike and forage for wild foods weekly. I’m not going to post my pics here, but some have seen me and know I’m not scrawny and malnutrition.