Best way to debug content deduplication when SSR hydration issues?

Context: I'm working on security 092 and ran into a decision point.

• What I’ve tried: basic setup + quick benchmarks.
• Constraints: limited time, want something stable.

Question: Best way to debug content deduplication when SSR hydration issues?

Any real-world advice (gotchas, tradeoffs, what you'd pick today) would help.