SAST has its place, DAST is great at finding the majority of flaws that the bad guys are going to uncover, and IAST offers unique approaches to complex situations. At a minimum, DAST should be your main focus. Step back and consider your application environment, your internal resources and expertise, as well as your budget.
Blog / Kevin Beaver
When every security flaw is deemed important, it creates chaos at the business level. In the short term, precious resources are wasted addressing such findings. Longer-term, these things add up to create true dysfunction in an overall security program which, ironically, makes the organization more susceptible to the risks that matter.
Shift left security incorporates security and testing phases at the earliest stages in SDLC, which can be done by integrating security testing in CI/CD pipelines.