You probably haven't gotten to them yet as void echoes are what I intended to be the "actual" little story for the game, so it's supposed to be more of a late game achievement.
Basically, once you reach Ascension 12, a small glowing "✦" symbol will start appearing somewhere on the screen, and during the latest fix I have also added a "void echo drifts..." writing under the symbol to make sure that the player understands what it is. If after achieving Ascension 12 and playing for about 5 minutes you don't see anything like that pop up, please feel free to let me know!
As far as corruption goes, surely that'll be improved as well. I wanted a somewhat active but not "too urgent" of a system (since it's an idler game after all) that would play into the idea of sacrificing small amounts of current pastry for a long-term future benefit, or rather absence of an incoming malus. But in true Lovecraftian manner, I wanted there to be a twist where sometimes corruption would actually give you bonuses, and later on in the game you would get an upgrade that makes corruption purely beneficial so it kind of enhances in my mind the feel of "giving in" to the whole dark Ascension theme. Sounds good on paper, but in practice I do understand the system is still pretty flawed!
I have left the early game almost completely unchanged with my last update, but I did tweak the later ascensions a bit (more detailed breakdown in the devlog).