This happens in many orgs. The truth of this situation is that it's engineering team's responsibility to build maintainable system, managers only care about results, risk management and team velocity.

The problem you're trying to solve is not that features get more prioritisation, but your estimations doesn't reflect the reality and your code-review process is broken as engineers are not spotting growing technical debt and refactoring opportunities and think that someone should give them a permission or create a ticket to work on that.

This is engineering culture 101 (look up the boyscout rule in software engineering).

Are they strictly focused on revenue and growth metrics? There might be a lot of relationship building needed beyond just the necessary ROI arguments.