We should reforest most of that land. It was previously mostly forested anyway, and doing so, together with a rapid phase-out of fossil fuels, would enable us to store enough carbon to halt global warming, restore biodiversity, and repair the water cycle to prevent droughts.
https://ourworldindata.org/deforestation#the-world-has-lost-...
> grazing animals are beneficial for the land
Not really.
https://www.oxfordmartin.ox.ac.uk/publications/grazed-and-co...
https://newrepublic.com/article/163735/myth-regenerative-ran...
https://grist.org/climate-energy/cattle-grazing-is-a-climate...
Your premise is flawed... outside of Antarctica, there's not really much empty land on earth.
We don't need to feed more, we just need to bring the education and standard of living if the world up. And maybe figure out how to make the people in developed countries to have sustainable birth rate...
https://www.eurekalert.org/news-releases/917471
A global shift towards healthy and more plant-based diets, halving food loss and waste, and improving farming practices and technologies are required to feed 10 billion people sustainably by 2050, a new study finds.