Does the company suffer from outages? (Not just have them—but actually suffer from them.) When there's a production incident, do a root cause analysis. If some of the root causes are related to coding and deployment practices, make notes of that. Start aggregating that information. Soon you'll have evidence that you can reduce outages by changing practices.
Does Product feel frustrated by development speed? Start taking surveys. How much time is spent on fixing past mistakes/dealing with bad code/discovering broken tests? That can be used as evidence too, when you want to start a conversation with management about pausing in the race to tie your shoelaces.