I’ve worked on a lot of open source projects and large proprietary code bases that I’d call not-a-mess. I’m not sure what that means to you, to me it means well-engineered in terms of quality criteria, rather than aesthetics, as it seems to be the case for many.

You sound very defeatist to me. I’m under the impression you’ve only worked in teams that don’t have an engineering mindset but rather throw-shit-at-the-wall-and-see-what-sticks coding sweatshops. You may want to look for a new company to regain your pride in your work..