To your point about increasing CO2 from farming plants: 40-66% of corn and 58%-77% of soy grown in the US is currently fed to animals, and we dedicate 5,000% more acres to growing feed crops than to vegetables[1]. Since between 3 and 10 calories of plants fed to an animal yields 1 calorie of animal product (depending on animal)[2], there would be room to either plant less, plant different, and/or use less emissive practices.
1: https://insideanimalag.org/feed-crop-takeaways/
2: https://en.wikipedia.org/wiki/Feed_conversion_ratio#Conversi...