> people would have nutritional deficits

Follow traditional cuisines that have worked out healthy vegetarianism. Don't buy fake meats.

> methane production would only drop by a max of 32%

Only? If I cut your salary by 32% would you say it isn't much of a drop?

> rice alone already emits 12% of world methane, this would increase

And would be more than offset by the methane emitted by cattle.

> 45% of the co2 from farming is plants. This would increase.

Why? Feeding people plants takes less plants than feeding animal plants and then feeding people animals.