Popularize the value of tests. Test, refactor, repeat. 2 years of legacy spaghetti isn't really that bad. I work for a company whose codebase is at least 14 years old in places, and there have only been serious testing efforts for 2-3 years.

Chances are, the code is a mess because nobody who knew better was empowered or motivated to advocate for a better way, but you have a hidden opportunity to be that hero.

Good luck!