You lack the basic understanding of the different methodologies mammals breakdown cellulose. Humans are not herbivores and without modern farming machinery it would be impossible to maintain a vegan diet except for being a fruitarian which results in a short lifespan and loss of teeth due to malnutrition. All of the information regarding our dietary evolution is easily available in the paleo archeological record. Regardless of someone's belief in evolution or creation, it is well documented that humans were originally believed to be fruitarians and transitioned away from it long ago. That's the reason we can still extrapolate the simple carbohydrates from fruits (fructose, glucose), the quick energy to keep our basic functions going to enable us to obtain a better source of sustenance i.e. either scavenge or kill an animal. The ability to survive on either animal or plant sources is why we are omnivores. Anyone who claims humans are herbivores is misinformed at best and delusional at worst.
I don't know how long you have been a vegan but I do know your health has begun to slip, you have stated it more than once. I am under the impression that you have exhausted your nutrient stores and are beginning to suffer the consequences. There are a ton of vegan influencers that have suffered the same and many are switching to the carnivore diet to rectify their nutrient deficiency, YouTube is full of their experiences. It comes down to the bioavailability of nutrients. Taking plants into the lab to extrapolate what they are composed of means nothing for the bioavailability for humans. We cannot digestively extract a high level of nutrients from plants, mediocre levels aren't even possible in most cases. Plants are exceptional medicines but they should not be the bulk of a human diet. There is a reason vegetarians, those that consume eggs, dairy, and in some cases fish, do OK. Their diet is augmented by rich animal sources, same for India. Ideology has nothing to do with biology, physiology, or anatomy. You would do well to eat some eggs, there should be no ideological issue with cohabitation with chickens. Give them a great life and their eggs will do the same for you.