Other people have put it very well here. Welcome to the job. Beautiful code from scratch is for your own time. You'll see that you'll learn this "monolithic"

Other people have put it very well here. Welcome to the job. Beautiful code from scratch is for your own time. You'll see that you'll learn this "monolithic" code base over time and that eventually you will play it like a violin and it will be somewhat enjoyable. If you want to write code from scratch and just blaze forward all the time join a startup. Less guaranteed job security but more fun for sure.