One issue we are having is that in MOST previously unexplored mountains, and by that I mean we have never even been in the oceans surrounding them, in our old seed, almost every single chest we find, at least 80%, have been completely empty. Combined that with probably a relatively low spawn rate of stone pois, and probably low onion seed spawn rate in chests combined with low spawn rate of loot in general, onions are going to be the hardest cooking items to find.