Imagine being able to walk into a meeting with your execs, the product owners, and other business leaders and say "My security initiative will make your delivery pipeline faster".
Do you think that'd be a compelling perspective for a business case?
Of course it would.
Bringing security into DevOps has to be focused on making that argument. DevSecOps done right is truly an enabler of the business, and those aren't just buzzwords. Be the hero, show your org that security isn't just a necessary evil, it's a competitive advantage. And start by baking it in as an integral part of the pipeline.