Its conflicting even in the sources. There's at least two lines that directly say "everyone who dies in battle goes to Valhal" However the sagas and Eddas are full of people dying in battle who are said to go to Hel. Similarly we have many people who do not die in battle who seem to believe they will be going to Odinn's hall. (academic speculation warning) most of the people who die outside of battle but still intend to go to valhal deem to be specifically Odinn worshippers. Perhaps there's a link there to the odinnic cult.
I mean literally every other food source is more environmentally friendly than meat. Animal agriculture is the number one cause of environmental destruction. Its absurdly inefficient as a food source. Hence why its the number one cause of deforestation and also why almost all food farmed in the world just goes to feeding livestock