The process of transformation is never "clean" though, you always have waste, and it is more wasteful to process nutrients through animals than plants in general. The higher your energy loss ratio, the more byproducts you'll likely generate per comparable "energy unit" output, and thus the less sustainable the solution.

Of course it is never clean. What is wasted, exactly? "Waste" products are not simply useless things that are disposed of to never be used for anything else again. Your use of the term "wasteful" in this context is meaningless. Like I said, energy is simply displaced differently. Such products often have other uses as well.

It is possible to grow some stuff seasonally, and to utilize greenhouses, soilless farming, and other solutions that can be sustainable in most places and result in a wide variety of food stuffs.

Have you ever grown crops? They tend to not grow when it is freezing. Soilless solutions will require a huge amount of infrastructure to feed everyone when the outdoors are unavailable. You are aware that all of these solutions require other resources such as electricity?

It is on par with the animal industry in regards to emissions in the current globalized setting.

It's as if you didn't read what I wrote.

The biomass of domesticated animals is enormous, and having them grazing and relocating would be a logistical issue nevertheless.

This is an issue for plants as well. They do require land. Surprisingly, growing food takes up space.

How much grass will there be in winter anyways?

Not much, probably. It is common practice to gather extra during the warmer seasons and dry it for use during this time.

Seems like some work will have to be put in either way

Of course.

Just land use, for instance, is a factor of 18 between vegan and meat-based diets.

Once again, you completely ignored my last post.

Would grazing and grass eating domesticated animals really beat that?

Seeing as we have not measured such a thing, I couldn't tell you with absolute certainty. I should point out that not all animal foods need to come from domesticated animals.

Similar things can be said about greenhosue gas emissions and other waste products.

Third time.