Change one variable
Keep the device, game region, server, network and test window as constant as practical. Compare the normal route against one VPN endpoint.
Repeat in the real problem window
Capture multiple runs during the hour the issue normally occurs. Record median latency, variation, packet loss and disconnects, not only the best ping.
Separate network symptoms from rendering
Low FPS and frame-time spikes are not packet loss. Check the game's network telemetry and device performance separately.
Limits
Worksheets in LagZero guides are instructions for your test, not LagZero benchmark results. Routes, ISPs and game services change, so no result is universal.