A client’s team spent a full week adding a CSV export to their admin panel. Two engineers, clear requirements, maybe a day of actual work. The rest of the time went to understanding existing code well enough to change it safely. That’s what I call codebase drag: when the codebase makes every task take longer than it should. It doesn’t show up in any dashboard or sprint report.
Why would you ask permission to do something necessary? Just do it any time you have a ticket in the area.
One place I worked at had a rule forbidding pure refactors. One, it’s no other department’s (or manager’s) business that you massaged something to be more useful. Two, what is QA supposed to do with a change that has no new features or bug fixes? Three, are you going to put “refactor” in your release notes?