A billion Chinese and more than a hundred million Japanese people seem to be telling us "Nothing too bad, don't worry so much."
It turned out in my life that I have not eaten bread since childhood. I don’t remember the reason “why it happened”, although many people in the family eat bread, for example, with soup or sandwiches. I cannot say that the lack of bread in the diet somehow affects my health. From time to time I go to the doctors, get tested, everything is normal. Everything is individual.
I can tell by my own example: the weight has decreased (by about 2 kg per month), the deficiency of B vitamins has begun (there are seizures in the corners of the lips, the skin condition has worsened).
The consequences will be individual, since each person has a different state of health and various external factors. Perhaps you get everything you need from other food sources or take vitamins in addition, then there will be no difference.
From my point of view, you should not give up something just like that. You need to understand the purpose of this restriction and be sure that it is achieved by restriction.
If the reason is possible excess weight, then it is better not to give up bread, but to choose the right bread and increase physical activity.
If the cause of celiac disease, then you need gluten-free bread.