Hmm , the crop its different in each biome , and to make it just have to use the cultivator in the earth to make it cultivable ( first option with RMB )
Heres the biomes crop differences
meadows : carrots , turnips
Black forest : carrots , turnips
Swamp : only turnips
Mountain : your sadness , there u cant crop
Plains : carrots , turnips , barley and flax
So the best biome its the last one but u need build almost a farm fortress to be fine guarded

For food and recipes see here
https://valheim.fandom.com/wiki/Food