Split Pea Soup, but peas aren't dissolving
I make split pea soup (with a hambone, which is an unavoidable source of salt - I don't add any extra salt until the very end) pretty regularly. I don't soak the peas. It takes more like 3 or 4 hours for the peas to dissolve. It's not a gradual process either - for ages and ages there are little peas floating in broth, and you can eat one and it's soft, but they don't lose their shape, and then the next time you stop by the stove, it's a uniform puree without having done anything. Just keep simmering, is my advice.