Veganism is real inconvenient and a real pain, not to mention not at all logical in many places, for example cold and arid areas, like cows will eat stuff you can't eat, and give you milk for sustenance, same with pretty much all milk producing mammals like goats, buffaloes etc.
Some vital nutrients like vitamin A, B12, D and K2, essential amino acids, creatine, carnosine, DHA and fats like cholesterol is present in low amount or absent in vegan diet.
They consume so much soy or soy based products, and unfermented soy contains antinutrients such as Saponin, soya toxin, phytates, trypsin inhibitors, goitrogens and phytoestrogens which is removed by the fermentation process.
These antinutrients have adverse health effects such as:
Decreases assimilation of calcium, magnesium, copper, iron and zinc

Interfere with iodine metabolism and increase the risk of autoimmune thyroid disease

disturb endocrine function, cause infertility, and increase risk of breast cancer.