The PR bottleneck is real, but hiring before you tighten scope is the wrong order. AI-generated PRs tend to be large because the agent has no reason to keep them small. That's a prompting problem, not a people problem. Enforce atomic PRs at the agent level first.
On tooling: automated checks (lint, tests, type safety) should catch the mechanical stuff so human review stays focused on architecture and intent. That's the only version of this that scales. A dedicated reviewer gets buried fast if every PR is 400 lines of generated code with no boundaries.