@hpod16
For total protein, I'd say skyr. If your protein goals include muscle growth, then definitely skyr, since it seems to have a greater leucine content than Greek yogurt.[1][2]

But environmentally speaking, I would avoid both. I'd go for a veggie protein shake instead: low in fat, low glycemic index, plenty of leucine, and sustainable.

[1] https://frida.fooddata.dk/food/1693?lang=en
[2] https://pmc.ncbi.nlm.nih.gov/articles/PMC7874106/