Maintaining code quality when nobody cares
You need to get the programmers together and agree on a coding guideline, a linter and other architectural fundamentals.<p>Then the gardening phase begins, which means no refactoring or warning or style fixes unless you touch the code to do something meaningful like a feature or bug fix. Leave everything you touch better than before. Dissolve big classes and functions into smaller ones. Write a test or two for the smaller side effect free function you just created.<p>It takes a ton of time and patience but every week the kraken loses a tentacle. And once most code feels untangled you can embark on a refactor since all of the parts are movable now.