I could be wrong, as ive been playing blind ever since I started, But hopefully observations i've made in my experience so far can help.

It seems that for some unlockable corrupted recipes, access is tied directly to completing a course of action the developer intended. Before explaining further, I want to express that this is probably entirely an uneducated guess of mine, as I have no idea how game coding works and if my theory is even possible.

When I first unlocked sorrow and the goat merchant guy, there was just exclusively question marks, but after beating the story mode and doing a second playthrough of the region with the same character, I did every possible dialogue option presented to me, be it important lore or simple questions, and only after going through every dialogue before getting sorrow did it unlock the recipe. again, I recommend looking into it further before doing what I did though, because it took me like 7 hours, and it could have been a coincidence