You’ve inherited a 300k lines of spaghetti code. What do you do now?

Quit.

The grain of truth in this is that organizations which have accumulated a lot of technical debt tend to continue to be organizations which accumulate a lot of technical debt.

Let’s say you take a new student job as a kitchen helper in a restaurant, and on day one, you learn that people there don’t really wash the dishes - they just make them look somehow clean.

Do you walk to your boss and tell him: “Hey boss, I got an idea, we could wash our dishes, what do you think?”

It is different if you have more of a say, as in, you are the chef. You could leverage that good chefs are hard to find. You could point at customer reviews with complaints.

But as an apprentice, I would advise to look for a better kitchen. Especially since tidying up 300 k lines of spaghetti code will take many person-years.