Every one of these has significant downsides to them (for you vegetarians out there, the phosphorous that leeches into the runoff is huge, affecting the ecosystem in ways we still don’t understand).
I get every point you make, but honestly, what is the real alternative?
Can you please expand on this? Animal agriculture is the primary cause of ocean dead-zones (due to fertilizer + manure run-off).[0] Because you're still eating plants - it's just that you're filtering them through another animal, and thus removing the vast majority of the calories, protein, and other nutrients that you would have got if you'd directly consumed the plants.
I don't think there's any debate on the relative environmental impact of a plant-based diet versus one that includes meat and dairy. It wins in terms of pollution, land usage, water usage, and basically every other metric.[1][2][3]
[0] https://www.theguardian.com/environment/2017/aug/01/meat-ind...
[1] https://www.theguardian.com/environment/2018/may/31/avoiding...
[2] https://waterfootprint.org/en/water-footprint/product-water-...
If you eat a lot of meat, then you have all the vegetarian concerns you can come up with plus all the concerns directly tied to meat plus the rest of the indirect concerns.
For example grazing livestock using hilly land that only grows small grasses.