In your experience, is it important to have written SLAs with data-as-a-service providers to ensure quality, availability and responsiveness?

I have just been asked by an exec from another function to audit a critical project in their portfolio which does not appear to be going well. I have some ideas based on my own PMO experience, but wanted to explore how peers might think about approaching such an exercise. Considerations: - outside my main role - risk of conflict with the leader providing project management services to this exec - sensitivity within the other function to potential criticism of their governance - readiness of the project team to provide relevant information