If you understand what are the metrics being tracked, and what are the primary goals that an initiative or product has, you can make a case.

We are an engineering discipline and engineering decisions can have revenue making implications. But it is hubris to assume why you should care about the nitty gritties of a codebase. It's the same way no one in leadership cares about the nitty-gritties of HR policies or accounting practices - people are hired to deal with the intricacies.

When I was a PM, I didn't have a difficult time making a business case for "keep the lights on" or tech debt work so long as I was able to attach tangible revenue implications (eg. X customer might churn because of subpar experience and we have both customer testimony and user stats showing that) or roadmap implications (eg. If we spend 6 months refactoring our monorepo, we can add new revenue generating modules every quarter instead of annually).