Expert PostgreSQL Architect Needed for 1-Hour Security Architecture Review (SaaS/RLS)

I am the founder of an enterprise HR SaaS platform. We have completed the V8.0 Master Engineering Specification for our core database. The system utilizes a 4-Zone PostgreSQL schema with strict Row-Level Security (RLS) and JWT context injection to physically isolate candidate identity data from employer workspaces for GDPR/Section 503 compliance. I do not need any code written. I need a senior PostgreSQL Architect (10+ years experience) to read a 3-page technical specification document and try to break it. I need you to look for structural flaws, RLS vulnerabilities, or logical errors in our data isolation model. Deliverable: Read the PDF, and give me a 1-page bulleted list of any security holes, or confirm that the architecture is structurally sound for enterprise deployment. Please answer this screening question at the top of your proposal: In one sentence, what is the greatest risk of using a SECURITY DEFINER function when combined with Row-Level Security?