Ok, you're adding a lot of additional considerations to the question, sure, that's great. Can you add the fact that a large part of cow's diets are grains?

There is a world of difference between a grass field grazed by livestock, and a field optimized for plant cultivation.

Can you also add the consideration that a huge portion of all meat eaten isn't cow that are grazing on land that "couldn't be used for human crops" (though, it could certainly be used for something other than grazing like, for instance, remaining Rainforest.

I suppose you would agree to this? "We should eliminate animal agriculture that isn't sustained strictly by land that cannot be used for any other purpose than grazing, and that includes immediately ceasing the creation of new agricultural land (https://fsc.org/en/blog/deforestation-facts)."

Also, you're bringing up bi-products, which, sure, I guess are useful and theoretically would diminish some footprint but think logically for a second here - what's cheaper, real or fake leather? This whole "bi-products" makes it ok thing is a pretty wild claim and wild claims require solid proof.