The problem is only 9% of the beef production and 30% of global sheep and goat production are feed using grazing
The rest so most of them are feed using some form of human edible plants and they would not be replaced by wild animals
These two statements exclude the middle. There is grazing. There is feeding animal edible foods. And then there is feeding animals inedible waste. Your same source organization (FAO) points out that 86% of animal feed is inedible by humans. Realistically, a very high percent of that would be destroyed in a landfill or in burning if they were not being fed to animals.
Of the remaining 14% of feed that is edible to humans, they are the worst sorts of calories, empty and non-nutritious carbohydrates. And they are largely fed to the animal intentionally at certain parts of the feeding process (the end) to produce the highest quality of meat. Why? Because it's a waste of money to give animals feed that you could sell to humans if you have no good reason.
Have you ever mathed out your actual carbon footprint, or exactly how your carbon footprint changed by cutting out red meat? Do you even know where your meat comes from to figure out if it's environmentally friendly beef or unfriendly? You might be surprised either that you did more than you think to help.... or absolutely nothing.